Bournemouth: South Coasting

In May 2015 Bournemouth clinched top spot in the Championship and achieved promotion to England's top division for the first time in the club’s history. When that happened there was much fanfare (deserved, of course), yet a few matches into 2015/16 season the novelty appeared to wear off a little and they haven’t received a great deal of coverage since. This despite having achieved safety from relegation twice in a row. It’s a shame really because a deeper look at them reveals some interesting tidbits and lessons to learn.

Their first season in the Premier League was shaky in the extreme. They finished 16th and five points above the relegation spots, yet had a worse goal difference (-22) than the two teams below them (Sunderland and the relegated Newcastle). Their non-pen expected goal difference however was -11.4.

This disparity stems from a defence with a tendency to collapse. Despite having a non-pen xGA of 48.4 they ended up actually conceding 63 goals. Parts of this may well be variance, but we have to also consider that goals were possibly easier to score against them than a team with a more defensive focus. They conceded 3 or more goals in 11 matches. Of those 11 only 5 were against teams who finished in the PL’s top 6, so this wasn’t a case of just getting bullied by the big boys.

Cut to the end of the 2016/17 season and they finished 9th with an improved goal difference of -12. So they sorted out that defence then? Well, no. In fact, it got even worse. They conceded 60 non-penalty goals and again conceded 3 or more goals in 11 matches. But this time with an expected goals against of 57.2. They gave up more shots (11.6 in 15/16 vs 14.5 in 16/17) and those shots were also closer to goal on average (17.7 metres in 16/17 vs 18.3 metres in 15/16).

There’s also little to suggest they’re getting defenders in front of shots and fooling expected goals models in a Burnley-esque style. Stratagem data for 2016/17 shows that they had 2 to 4 players in front of the shot 72% of the time and 5+ players in front of it 13.7% of the time, both numbers being bang in line with the league average.

The improvement they did make, such as it is, lay in the attack. Last season they posted an iffy non-pen 36.9 expected goals for tally. This season that has moved forward to 43.0 xGF, a number more befitting a midtable finish.

 

bmoth

Despite this improvement, however, open play is not where Bournemouth’s bread is buttered. They scored 7 penalties in 16/17, joint-first in the PL alongside teams you’d perhaps ‘expect’ to be there: Tottenham, Liverpool and Man City. It could have been even more as their 10 penalties won overall was the best in the league.

This is an interesting quirk to Howe’s Bournemouth. It appeared absent in 15/16 when they only won 4 penalties, but if you look back to their time in the Championship it becomes clear it is a point of emphasis. In 2014/15 when they achieved promotion and the Championship title they won a staggering 16 penalties, a full 7(!) more than the team who won the 2nd most.

This could well be a result (intended or otherwise) of Bournemouth’s playing style. Per Stratagem data, they were 8th in the league in key entries into the box via a run this last season:

key entries euan

The seven teams that were ahead of them are the league's actual top seven, so in this regard Bournemouth are the best of the rest. The evidence points towards Howe telling his players to put their heads down and run when near the opposition box, and to some degree it’s working. Something he should be given praise for as most teams are dying for anything similar that separates them from the morass. Whether it’s a sustainable edge is another question entirely. One that depends on how thoroughly their opponents are scouting them and whether their coaching staff can drill it into them to just not foul.

Transfer business needs to be addressed because it’s been a bit of a bumpy ride in that department. There has been a degree of success. Benik Afobe, Josh King and Nathan Aké on loan were all agreeable moves. Problem is these bright spots have been in the margins of a wider, more confusing transfer picture.

Jordon Ibe - a player who, with the best will in the world, didn’t even flash much talent at Liverpool - was brought in for £15m. Even if he did turn out to be the absolute bee's knees Bournemouth were rumoured to have very generously offered Liverpool a buy-back clause, all but dooming the deal to be an overpaid loan at best and a complete waste at worst (Ibe played a shade over 1000 minutes in 2016/17, registering no goals or assists).

This week, as you’ve no doubt heard, they picked up Jermaine Defoe on a three-year deal from newly relegated Sunderland. There’s plenty of reason to believe that Defoe isn’t all he’s cracked up to be but let’s put that to side for a moment and assume for the sake of argument that the conventional wisdom (‘he gets you goals’) is correct on him. He’s 34-years-old, turning 35 in October yet has been signed up on a three-year deal.

Josh King alone scored 16 for Bournemouth in 16/17 as a primary option, not to mention Afobe and Callum Wilson’s contributions. Defoe had a whole team built around him last season and notched 15 goals, 5 of those being penalties (Is that it? Did they bring him in to take all these penalties they’re winning? He certainly didn't win any penalties himself last year). There's no case for him as a creation option either: Last season Defoe produced fewer key passes (20) in 3323 minutes than Afobe produced in 1454 minutes (23).

(While we're here: Bournemouth were dead last in terms of regaining the ball past their opposition's 18-yard-line via a turnover this season, and by a large margin too. Having a 35-year-old up front doing the pressuring will not help with generating those sorts of opportunities.)

Then you have all these players hanging around the squad seemingly without much purpose like Lys Mousset or Max Gradel. Howe has been loyal to his starting group of players, but left others apparently marginalised. Not to mention the strange Jack Wilshere experiment. It’s very hard to get a grasp on what the overall plan is, if one exists.

That’s Bournemouth in a nutshell really. Their supporters should probably feel relatively at ease as they head into a third year in the PL. The team’s overall profile is likely complete enough to expect safety for the near future, barring a freak season. An accomplishment that is fairly ahead of schedule for a club their size. Yet with a defence as dodgy as theirs that margin of error is is always going to be a bit slighter than you’d like. However, Aké and Begovic are decent defensive signings that could be the bedrock for good things to come and may well address this. 

At the moment they scan as a side devoid of a direction outside of just keeping on keeping on. Cut out the head-scratcher signings, tighten up the defence and we could be looking at a Premier League mainstay. As it stands though, there's plenty to work on.

(Parts of this article were written with the aid of StrataData, which is property of Stratagem Technologies. StrataData powers the StrataBet Sports Trading Platform, in addition to StrataBet Premium Recommendations.)

More Statistical Transfer Shopping - Wide Forwards for the Champions League

Imagine for a second that you had an enormous early mover advantage in the world’s most popular sport. Through buying a data company that had better data and better people than all of your competitors, you could suddenly see with clarity into a market worth billions every year. It would now be possible to find the best young gems for discount prices and turn them into superstars. It would also be possible to find +EV ways of playing football, which in turn should bring more success than ever before. Now imagine that for whatever reason, you did basically nothing with this advantage, allowing your rich competitors to catch up to you – and potentially surpass you – because they actually execute on the information. Welcome to Arsenal! Catching Up When last we left our intrepid rebuilding project, we had identified a number of useful-though-expensive center forwards, and we also suggested a few young midfielders, an area where Arsenal still have needs in spite of recent investment. That was before the rumour came about that Naby Keita wanted to leave RB Leipzig. The rule is simple: If you can get Naby Keita, you get Naby Keita. Period. And especially if he costs considerably less than Paul Pogba. Ignore what I said earlier and focus on Naby. If that falls through, as our hopes and dreams always do, then go back to the aforementioned list of midfielders and make it happen, but not until! And now… on with the adventure. Wide Forwards As noted in the earlier piece, if Alexis leaves, Arsenal have Alex Iwobi as a starting left forward and Theo Walcott on the right. Meanwhile, Liverpool will now have Mane and Salah meep meeping all over the place. This would be… suboptimal. As a result, I started squinting at this, which is either a modern art exhibit about circles and bubbles, or it’s the entire data set of players last season on a scoring scatterplot. ooo_pretty Wide forwards on a team with league title aspirations need to do three things

  • They need to be able to score goals
  • They need to create for their teammates
  • Some meep is required.

meepmeep_roadrunner Because it’s Arsenal, they also need to be good passers.  This is a huge ask, and in reality there are few players in the world who fit the requirements exactly. The first name that comes up on the list is Memphis Depay. *audible groans from the audience* Look guys, I’m just analysing the data and it says Memphis is very good and has a very rare skill set. *more shaking of heads. someone throws a tomato* AHEM! Given the inevitable complaints on this line of analysis from people who think he was bad at Manchester United despite the fact that as a team, they only took as many shots per game as Big Sam’s Sunderland, we’ll fast forward to other candidates. Salah? Taken. Marcos Asensio? Ha! Emil Forsberg? Not happenin'. Kingsley Coman? Just arrested on a domestic assault charge so maaaybe not. Bertrand Traore! Just moved to Lyon for a price that was scarcely believable when reported. Unsurprisingly, this is hard. How about this guy? Keita - Italian Serie A - 2016-2017 Can play left forward and center forward. Physically awesome. Ran hotter than his expected goals numbers last season, but the underlying numbers were still quite good. Plenty of meep and an absolute handful physically. Also only has one year left on his contract, so won’t be as expensive as other targets. Ángel Correa - Spanish La Liga - 2016-2017 I feel like this kid gets zero headlines, but his stats are amazing. Plays everywhere behind the striker and almost fully two-footed. Excellent dribbler, and good strength for a smaller guy. Only has two years left on his deal at Atletico, so maybe now is the time to turn his head for bigger money. Atletico are a great team, but the Premier League can certainly pay him far more. The Dortmund Crew So Dortmund actually have three young players that would interest Arsenal. They probably won’t sell any of them, but Ousmane Dembele, Christian Pulisic, and Emre Mor all look like they are right on the cusp of being world class wide men (although Mor kind of plays everywhere). dortmund_kids Dembele is one of those players where I don’t fully agree with the passing model. His high risk-high reward style is hard to credit properly, but he is lightning in a bottle on the pitch and already one of the best creative wide men in the world at age 20. Mor gets less hype, but his style feels inherently more Arsenal. Small sample in Bundesliga last year – he turns 20 in July – but he also completed nearly 6 dribbles a 90 last year in Denmark and passing ability is top notch. Finally you get The Great American Hope.  Like with Dembele, Pulisic spoofs the passing model a bit by being another high risk-high reward player. By signing Pulisic, Arsenal would not only get a great young player that fills a need for the club, they would also dramatically increase American media attention for the club. All good, all slightly different, none very likely to move. Sigh. Now we hit the squiffy bits. This is the problem with transfer shopping in a busy market without the buying power that Manchester United or Real Madrid have. Many years you actually need to take risks. Perfect players for your squad/system/needs are not available. Thus you end up making calculated gambles – often with younger players that have good baselines – that they may develop into something special. This is exactly what Dortmund are doing right now and it is absolutely the right strategy. It’s also what Arsenal should have been doing since the moment they bought StatsDNA, but they have not. And the thing is, so many of these risks are easy to justify. Mane, Sabitzer, Timo Werner, de Bruyne, Depay, Eriksen, Dybala… all young players who had clear stats profiles that they were likely to be good to great in the future. Yes, some don’t work out – that’s why they are risks – but if you can’t afford to buy elite players any other way, then you need to take some gambles just to continue competing. The following guys have more risk involved and might be less obvious targets, but they do have interesting output. Two from Brugge brugge_duo One big man, one small. Wesley is a CF who used to be at Overheul-favorite Trencin, but posted big numbers in a half season at Brugge. Izquierdo is a tiny Colombian whose game scouts a bit like a discount Alexis. He's been on the "Interesting" list for a few years now. Shooting locations could use some work, but the rest of his game is probably good enough for a move to the Premier League. (Yes, they are both South American so there may be some work permit struggles, but grease the wheels already!) Eredivisie The most divisive talent league in world football. When the average age is this low, players at full maturity have an easier time. Defending isn't great overall. The quality of the top of the league is very different from the bottom, and that also causes issues when evaluating talent who is effectively beating up on League One players instead of Europa League finalist players. THAT SAID… there is talent in the league and it is undeniable. There are four guys that Arsenal should take a long, hard look at right now and hope that they turn into something special for the future. The first three are from Ajax. Dolberg isn’t ready to lead a Premier League line, but he is already special. Teammates David Neres and Justin Kluivert also look very interesting, despite their best games coming against teams that were... uh... (BE POLITE)... not great, Bob? I usually hate big fees paid for Brazilians, but Neres – like countryman Gabriel Jesus – looks like he could end up being an astute purchase. [Small sample and weak competition caveats ALL over this one, and yet when you trip the rarely-if-ever-tripped Messi Warning Bell, you definitely get a closer look.] David Neres - Dutch Eredivisie - 2016-2017 I’m not saying definitely try to buy him. What I am saying is do a whole lot more scouting and research and THEN make a decision. The last guy I find super intriguing is Steven Bergwijn at PSV. Some of the same caveats as above apply, but his output is interesting enough that once again, you should take a very long look and see if everything else adds up. Steven Bergwijn - Dutch Eredivisie - 2016-2017 Thomas Lemar In lieu of boring right back recommendations, I wanted to just take a quick moment to give my feedback on Thomas Lemar from Monaco. He’s excellent, and I’ve been interested in him since his Caen days. Passing ability matches up with what we’ve come to expect from Arsenal, he’s good in space, and he’s fast. The problem – if you want to call it that – is the bulk of his assists last season either came via set pieces or on crosses to the far post on the break. I’m not sure I would let that stop me from signing him. He’s a lovely player. But I’m just not sure Arsenal’s style of play or general indifference on set pieces really maximises his skills. Conclusion The reason I started writing this was general frustration. I wanted to map out what was possible this year in terms of Arsenal upgrading the squad enough to contend for a title. To me, Arsenal feel a bit like Manchester United as we entered the end of the Fergie era, except without the Fergie bit (or the Pulis-like set piece execution from Fergie's last two seasons). The squad has aged in a number of key positions. The academy no longer provides talented replacements. More money has been spent from time to time, but overall quality seems weaker than a number of competitors, including (and unusually) Spurs and Liverpool. Manchester United spent something close to £500M in the last three years to try and rebuild that old Fergie squad to a title-contending standard, and while they probably paid too much and had some notable misses, the fact remains that the investment in new players was necessary. With Arsenal… who knows? A couple of scenarios to ponder Max Money(£) Mbappe – 110M Naby Keita – 70M Memphis – 55M Ousmane Dembele – 70M Right Back – 40M More Sensible But Good (£) Lacazette – 50M Keita Balde Diao – 35M Angel Correa – 45M Jorginho - 45M Right Back 25M Please God, No (Hauntingly Likely) Alexis Leaves +60M Ox Leaves +35M Ozil sees out contract - 0 Joel Campbell Comes Back – 0 Theo - 0 Welbz + Giroud – 0 The Interminable Contract of Mathieu Debuchy - 0 Thomas Lemar! - 25M (release clause) Regardless of how it works out, Arsenal's summer is wildly complex. Two of their best players are pushing for new, big-money deals toward the end of their careers and with one year left on their contracts. The outcomes there have knock-on effects for every other piece of business Arsenal will do this summer. As a long-time fan, I have been conditioned to hope for the best but to expect the worst. As someone who does transfer evaluations professionally, I have to say that the possible outcomes are certainly better than I feared. I doubt we'll see any of the high end deals happen at either North London club, but Arsenal could still do a lot of good business despite seemingly being quite late to the party. Or... they could sit on their hands, penny pinch on prices and wages, and end up with pretty much nothing, just like the olden days. Thanks for listening! Ted Knutson @mixedknuts ted@statsbombservices.com

Reloading the Arsenal – A Summer Transfer Shopping Spree

After years of predicting it, The Guardian football writers finally got it correct - Arsenal finished the 2016-17 Premier League season in fifth place. And it wasn’t an unfair fifth either. Though they were only one point behind Liverpool, Arsenal scored fewer and gave up more goals than any of the teams who finished above them. As James Yorke pointed out last year, six of the clubs will be looking to make the Champions League every season. Even if one of them wins the Europa League, like Manchester United did this year, only five of them can possibly qualify. Relegation to Thursday Night Football (translation: Europa League) finally happened. At most football clubs, after years of sustained Champions League appearances this finish might yield a change at the top. Not at Arsenal. Barring unforeseen circumstances, Arsene Wenger and his entire coaching staff will be back for another two seasons at least. What Arsenal face now is a better coached Premier League than at any point in history. The other big six clubs have more money than ever, and seem to make (mostly) smarter decisions. The rest of the league has enough money to buy serious talent from around the world. There’s even a reasonable case to be made that the other big clubs also have better, more productive academies. So I found myself asking: How can Arsenal rebuild themselves to compete and win a league in this environment? Today I'm going to explain what positions I think need replacing or upgrading, and identify talents I would go after if I wanted to rebuild Arsenal for the future. Assumptions Rule 1) Coaching stays the same for now. This means tactics also likely stay the same, so unless Arsenal magically adopt a destructive middle block or an aggressive high press, the defensive output is likely to be high variance. This is an unfixable flaw that would have been solved by hiring someone like Thomas Tuchel. Rule 2) Alexis is leaving. Mesut stays. Ox…? We have to make SOME assumptions on who stays and who goes, and this is my guess. This means we have to find a way to replace a flexible wide forward/center forward who can dribble, pass, and scored 24 league goals last season. Simples. (Note: this is a lie. This is NOT simples.) Rule 3) Money is available. Look, I’ve heard the rumours that Arsenal could run afoul of the new Premier League money rules, but let’s be honest – if Kroenke really wants to support Arsenal financially, he can. He could sell to Usmanov. He could make ASDA (owned by Walmart) the official grocery partner for Arsenal to the tune of £60M a year and pay them back out of pocket. He could plant a magic commercial money tree in the center of Emirates stadium and use the fancy pitch lights to make sure it continues to produce exactly as much money as the club needs to rebuild. (Note: If you are looking for precise monetary and cash flow realism, I recommend reading someone else’s piece where they personally rebuild Arsenal’s squad via the transfer market and not this one.) Rule 4) We’re still being realistic. Wait… didn’t he just say…? This rule means that we can’t just buy awesome players for infinite money from whatever team we feel like. Kylian Mbappe is vaguely realistic. Messi, Ronaldo, Pogba, etc are not. Excellent, now that we have lost half our audience via rules lawyering, we can continue on to discuss what we’re actually buying. The Needs Starting CF Starting LWF Starting RWF Starting CM/DM Starting RB (sort of) Remember, Alexis is leaving. This leaves Arsenal with Danny Welbeck and Olivier Giroud at center forward. (We’re assuming that Lucas is leaving as well.) Giroud turns 31 in September and isn’t getting any faster. He is genuinely great as a sub and has had a very good Arsenal career, but not starter material in this league any more. Welbeck hasn’t played 2000 league minutes since 2011-12. The last two seasons combined he’s around 1300. A center forward is needed. It leaves Alex Iwobi as your starting left wide forward. We love Iwobi but um… yeah. We’re also not entirely sure Iwobi is a wide forward, but we are definitely sure he’s not Alexis. It leaves Theo Walcott as your starting right wide forward. Walcott turns 29 next year and unsurprisingly, is showing signs of decline. He’s still good, but he never plays a full season due to constant injury issues. Interlude: The Funny Thing About Arsenal and Injuries As someone who has studied this professionally because we really care about it for transfers, I don’t think Arsenal actually have an unusual number of injuries at the squad level. I do think Arsenal have a lot of injury-prone players who keep getting signed to new contract extensions. For whatever reason, Wenger almost never cuts his darlings. He keeps players that he likes around for ages, many of whom have had serious injuries at various points in their Arsenal careers. Rosicky. Diaby. Arteta. Wilshere. Walcott. Ramsey. Cazorla. Oxlade-Chamberlain. Now Welbeck. Broken legs, ankle issues, Achilles issues, ACLs… when players suffer those, they tend to get injured after at a more frequent rate than before (especially withbroken legs and Achilles problems), and they never go back to a normal injury profile. The question can be asked whether Arsenal broke them in the first place, but the truth is that when you keep injury-prone players around as long as Arsenal do, you need to just expect that they will stay that way. This unfortunately creates a huge squad drag where your best players seem to only be on the pitch 60% of the minutes in a year, and often not at the same time. Compare that with what Chelsea and Leicester and Chelsea again had going the last three seasons in terms of squad continuity… We now return to our story. Ox is the wild card here. I think last season was the first time he’s truly come into his own. His best position seems to be as a wing back, but he’s also a good center mid in more of an 8 role. He is one of the fastest, best dribbling players in the league. So what’s the problem? Well, he only has one year left on his deal. He’s also just coming into his prime, knows he can command a good salary on the open market, and probably wants some assurances on playing time and position. The other question is: can he score goals? His output looks like a creative midfielder. Arsenal need goal threats from their wide forwards and for all his good traits, Ox has never really shown that, so even with Ox around, Arsenal need a scorer from wide. Next we hit the midfield issue. We are not taking any wagers on whether Cazorla will be healthy enough to perform next season. This leaves Arsenal with some combination of Xhaka, Elneny, Ramsey, Ox(?), Coquelin, and Iwobi in the midfield 2. Xhaka is a talented passer, but a bit slow and a brainless tackler. Coquelin is a very busy defender, but not versatile. Elneny is still a bit of an unknown – our passing model loves him but Arsenal fans have barely seen him play across 18 months at the club. Iwobi is a great young passer, but probably not a CM and not ready to dominate games defensively. And finally you get to Aaron Ramsey… I like Ramsey. I also have strong criticisms of Ramsey that I think are valid. These two viewpoints can exist at the same time. Aaron Ramsey is an excellent attacking passer. He is also great at getting himself into good shooting positions. The problem? He can’t finish. ramsey_xG_vs_GOne of these things is not like the other… one of these things is not the same.” So his greatest strength is getting into excellent finishing positions. And his biggest weakness is being a poor finisher. That’s a pretty cruel tradeoff. If this were a role-playing game, you’d just say fuck it, and re-roll. The other issue with current Aaron Ramsey is the defensive output. I’m not sure he’s a two-way player any more. Part of this may come down to role – he has played wide or more as a 10 in recent seasons – but the Ramsey that everyone fell in love with were the 12-13 and 13-14 versions that had him blowing up play constantly in addition to attacking. Modern Rambo does not do this. If he’s not capable of doing that, then Arsenal need a different option to be able to play Wenger’s midfield 2. If he is capable of doing this, then Arsenal desperately need him to start doing so again, because a midfield that only has Xhaka or Coquelin doing the defensive work is unlikely to win the league. Finally we get to right back. Pop quiz! Please match the following players with the number of possession-adjusted tackles they made per90 last season.

  1. Bellerin
  2. Pedro (Chelsea)
  3. Victor Moses

 

  1. 2.25
  2. 1.80
  3. 1.04

After a lot of study, I think Hector Bellerin is an ideal wing back. He’s very fast, pretty good at attacking, and uh… well, that was pretty much it last year. In previous seasons he had more defensive output, but last year was very low. This is weird, as fullback is a position that needs to defend. Whatever you think of them, accumulating tackles and interceptions - especially at fullback - is usually a solid indicator that "defending is occurring." Even as a back 4, Hector didn’t do that much. Maybe that changes this year? Regardless, beyond Bellerin, the right back options in the new season are currently Jenkinson, who is probably a below average PL fullback, Callum Chambers, who everyone feels is a center back, and The Interminable Contract of Mathieu Debuchy. You could be forgiven for thinking Debuchy had changed clubs last season. Or gone out on loan, like he did in 15-16. According to Transfermarkt he had 266 minutes in all competitions last season, which includes 250 in… Premier League 2. And somehow, impossible as it may seem, Debuchy still has another TWO YEARS left on his contract! 2019!!!!!11!1111! *head explodes* The answers to the earlier pop quiz are Pedro = 2.25 Moses = 1.80 Bellerin = 1.04 Confusing stuff, I admit. Antonio Conte is a fucking magician. Even if you think Bellerin is god’s gift to right backs, Arsenal still need a viable backup option in case he gets injured, and none of the current options are good. And So It Begins Let’s start with center forward, since that one gets all the headlines. The two best guys on the board are Mbappe and Alvaro Morata. Like I said in the Valuing Mbappe piece, I don’t think £100M is wholly unreasonable for the young Frenchman and apparently neither do Arsenal. Morata is likely to be a bit cheaper – probably in the 70-90M range with add-ons – but despite my long-term love for the Real Madrid player, at this point I think Mbappe might actually be the better option. Álvaro Morata - Spanish La Liga - 2016-2017 (1) After those two guys, things completely fall apart. None of the big names are gettable or fit the age profile we want. If Arsenal are spunking big money on a top tier forward, he needs to be able to lead the line for the next five years. Additionally, they don’t need another good backup forward, which is what Lucas Perez was for them last year. Lacazette is the next biggest name on the rumour mill, and I suggested him for Arsenal back in January of 2014. 3.5 years later, Lyon have had the best of him and Arsenal are still sniffing around. I still think he’s good, but at 26, I have concerns about what an elite pace striker will look like on the back half of a five-year contract. The next two best targets, at least in my mind, are both players owned by English clubs. The funny thing is, the big clubs almost never sell to each other. They all buy from Southampton, they all sell cast-offs lower down the league, but they almost never make deals between themselves. However, in terms of statistical profiles, Kelechi Iheanacho stands out by a country mile. Kelechi Iheanacho - English Premier League - 2016-2017 (1) The above is a combined plot across the last two seasons of Iheanacho at Manchester City. He's really quite good. The other player owned by an English club that I would go after is Tammy Abraham. He had an awesome season last year in the Championship on a pretty bad team, he has great size, pace, and strength, he can play both wide and central, and he can pass. Would I pay £30M in the current market for Abraham? Easily. £40M? Probably. £50M? Eh. As long as there were no buybacks and the sell-on clause was reasonable I would think long and hard about it. Yes, it would be a gamble, but I think Abraham is a more versatile player than Lukaku at the same age, and his upside is probably even bigger. No way Chelsea sell him to Arsenal, by the way, so it’s all just pie in the sky. On the other hand, I pitched a Traore and Abraham for Alexis swap to Chelsea super fan Jake Cohen two months ago, and he got visibly excited by the deal, so maybe Arsene should call Emenalo and get busy. If all of those fall through, you end up with even more risk for what are likely to be big prices.

  • Alassane Plea probably would have been on this list before the knee injury.
  • Diogo Jota is certainly worth scouting.
  • Belotti is going to cost a fortune and would be moving from a weaker league.
  • Modeste is too old and doesn’t play the right style.
  • Werner and Kramaric are both staying in Germany and playing the Champions League.

In short, finding a top tier center forward for anything approaching a reasonable price is nearly impossible these days. Yet you'll still find plenty of talking heads out there both castigating teams for the prices they pay while eviscerating teams because they didn't manage to bring quality players in during the window. ¯\_(ツ)_/¯ Verdict: Any one of Mbappe, Morata, Iheanacho, or Abraham would be great. Lacazette (guide price: £50M) still makes sense, but is the least exciting of the lot. After that, you're gambling and hoping you win. Central Mid/Defensive Mid Last spring, I told everyone that Naby Keita would be the one midfielder in the world I would pick for Arsenal (or Liverpool). A fantastic athlete, he’s great at both ends of the pitch and exactly the type of midfield dynamo Arsenal needed. The world responded with, “Who the fuck is Naby Keita?!?” which at the time was a pretty fair question. Naby Keita - Austrian Bundesliga - 2015-2016 One year on, Naby finished 2nd in the German Bundesliga with RB Leipzig in their first ever season in the Bundesliga. From what I hear, there is no chance he’s moving this summer. My second choice for midfield dynamo would have been Corentin Tolisso of Lyon. Unfortunately, last week Tolisso made a €50M move to Bayern Munich. Du schnoozen, du loozen, ja? After those two guys, things get complicated. There just aren’t that many players in the world who fit the “ridiculously well-rounded midfielder” skill set that Arsenal require, so you start to make hard choices. My opinion is that we can sacrifice a bit of attacking output in exchange for guys who defend. Longer term, maybe we are looking for more of a Santi instead of a Ramsey, but honestly we’ll be perfectly happy with someone really good. Three names… Jorginho - Italian Serie A - 2016-2017 Óliver Torres - Portuguese Primeira Liga - 2016-2017 (1) Rúben Neves - Portuguese Primeira Liga - 2016-2017 I don’t think Arsenal can get a Rabiot or a Kovacic, but one of these three guys might be possible. Jorginho is probably the best right now. Torres might be the best attacking player of the three. And Neves is still young, but almost certainly a midfield prodigy. Verdict: I have no clue. I think the most likely scenario is that Arsene chooses to continue on with his current midfield and focus on other areas of need. La Pausa This is already long, so I’m going to break it here and continue next week with suggestions for the two wide forward positions, a right back, and some tactical discussion to wrap it up. Thanks for reading! Ted Knutson @mixedknuts ted@statsbombservices.com  

Mohamed Salah: Signing of the Summer?

It looks like Liverpool are going to make a high end acquisition for their forward line as they close in on the signing of Mohamed Salah. However a little scepticism lies around the deal with Salah having appeared to fail when appearing in the Premier League before at Chelsea and possibly a prejudice against Serie A form translating into the Premier League.

His fee will not be cheap, but when factored against other fees paid this summer, £35 to 40m does not look excessive and his signing will solve a simple problem for Liverpool. With a first choice front three of Philippe Coutinho, Roberto Firmino and Sadio Mané, alternatives have required a different style with Divock Origi and Daniel Sturridge more traditional strikers. Strength in depth is high on Liverpool's priority list and they simply haven’t got a plug and play replacement for their first choice forward three. Salah will offer exactly that with an ability to both score and create.

Performance

In terms of performance, Salah has had two phenomenally successful seasons in Serie A for AS Roma after a promising loan spell in the back half of 2014-15 for Fiorentina. Across that period he has scored 35 league goals and contributed twenty assists. The goals have come at a rate of around one every two games and the assists at a rate of one every three. This is a top class return for a wide forward and scarcely replicated across the top leagues. His expected rate slightly lags (~0.65 expected goals and assists per game, compared to a reality of ~0.8) but is still top class and goals have come from all over, with five from outside the box too. He’s not quite the dribbler his reputation suggests, at least in his time at Roma, and in this he differs to Liverpool’s first choice front three, but potentially that may change in Klopp’s system.

His open play expected assist rate, based on the value of the chances he created as measured by expected goals, lead Serie A in 2016-17 building on a strong 2015-16 total:

spop 2 seasons of serie a2

We can see that in 2016-17, he was well capable of creating chances in dangerous areas:

salah xa

And he managed to find pretty good locations for his own shots too, albeit with a bias to the side he operates on:

salah 1617a

You want a creative goalscorer entering his prime years? Salah ticks all the boxes.

I ran a few checks to look for what he does in comparison to his peers and came up with a short list of players across the last two seasons in Serie A and the Premier League:

  • Alexis Sánchez 2015/16
  • Alexis Sánchez 2016/17
  • Philippe Coutinho 2015/16
  • Philippe Coutinho 2016/17
  • Lorenzo Insigne 2015/16
  • Lorenzo Insigne 2016/17

These er… “deep statistical checks” represent players of Salah’s ilk who have hit and exceeded the same simple benchmarks he has. If you look “up” from Salah, you get these guys. This is good company he's keeping and the combination of creativity and goalscoring ability is again uncommon.

Concerns?

No transfer is a cast-iron certain hit. However, recently Liverpool have done well in identifying types to fit into their attacking corps. Sadio Mané and Roberto Firmino have both proven to be excellent signings and could be forecast to be so ahead of time. We know that Michael Edwards and his team are analytically minded, and both these players were easy to rate highly statistically--like Salah--prior to joining Liverpool.

So what complaints might we have?

“He’s only performed in Italy”

This might seem appealing, but sidesteps the successes in Liverpool’s recruitment. Sadio Mané arrived fresh from a 6th place finish for Southampton, Roberto Firmino came after Hoffenheim had finished eighth in the Bundesliga, Luis Suárez arrived from the Eredvisie and Coutinho was spotted as a kid who was struggling to get gametime at Inter Milan. That Salah has been performing at a high level for the second placed team in Italy is a higher starting point than all these players, which kind of negates the entire argument.

“He failed at Chelsea”

Eh, back in those days, who didn’t? He landed at Chelsea in the January transfer window of Jose Mourinho’s first season back. 2013-14, got around 500 minutes of play, then all but vanished the following year before going on loan to Fiorentina. Chelsea had Eden Hazard and Willian in those seasons, and Mourinho often preferred to play a worker such as Ramires on the opposite flank to his main creative in Hazard while Oscar, though also young was part of that first team unit. Salah’s dynamic attacking style was only ever likely to appear fleetingly at that juncture, and it was unrealistic to expect him to dislodge those senior pros. Kevin De Bruyne and Juan Mata left in the days before his arrival, so it’s not as if routes to the first team were straightforward at all.

The arrival of Cesc Fàbregas in time for the 2014-15 season worked against Salah for two reasons, insofar as Fàbregas now inhabited a position that Salah’s rivals for a starting spot could have occupied. On top of that, the Spaniard’s inclusion meant that once more Mourinho was potentially less likely to empower a pure attacker on the right side of his 4-2-3-1.

Are there any other obvious problems? The African Cup of Nations for one. It won’t come into play til 2019 but now both Liverpool’s prime right sided attackers will be vanishing for weeks on end. And that highlights a secondary issue: really, Salah’s preferred position on the right side is the same role that Mané inhabited all through 2016-17. Each is versatile enough to move into the centre as well, but it might take some tinkering to get right. A plus point is that the purchase of Salah does also offer the tantalising prospect of dropping Coutinho into midfield and running a front three of Firmino, Salah and Mané. The club is spending £35-40m on a player here, and you’d presume that although he will enable rotation of the front three, it would be desirable to get them all on the pitch at times too.

One possible aspect of his play that might not be best served by Liverpool’s striker free model, insofar as he linked up exceptionally well with a resurgent Edin Džeko, particularly last term. Salah created 22 chances for Džeko in 2016-17 of which seven became assists--only Ousmane Dembélé to Pierre-Emerick Aubameyang was more lucrative with ten. However, in 2015-16 Miralem Pjanić to Salah was Roma’s most regular chance creation combination, to show he is capable on either end of the creative process. A strength in intelligence and timing is supported by the fact he made 17 shots from logged through-balls and scored six times across two seasons.

Concerns abated

Salah will arrive at Liverpool with an expectation to be a big part of the first team rotation. This transfer and the stage of his career is very different to his previous visit to England. There are sufficient positive aspects to feel that concerns about this transfer can be generally disregarded.

Liverpool are acquiring prime talent who at 25 years old is likely to spend his best years with them. Salah’s profile appears so solid at this point that nearly any club in Europe could realistically enhance their squad by acquiring him. There is talk that Roma need to sell to balance their financial considerations, and if that’s the case, then Liverpool have stolen a march by stepping in and getting the deal done. I thought Mané was about the most surefire signing of the 2016 summer window and I feel similarly now about Salah. Does this mean he’s a guaranteed hit? No, but once more Liverpool are showing that their process of identifying attacking talent and acquiring it is generally sound. The chance that he succeeds clearly outweighs the risk that he will fail.

__________________

Thanks for reading.

@jair1970

While writing this, I came across this piece by Ray Hamill @finermargins. Well worth taking a look, and had I not already half written my piece, I could've just tapped the retweet button and saved myself a job 🙂 Anyway, check it out.

A Quick Lesson on Forward Stats featuring Zlatan Ibrahimovic

At one point in the 16-17 season, I posted a radar featuring Zlatan Ibrahimovic's xG stats and basically exclaimed that his output so far was exceptional and that goals would come.

This was... controversial. And as with almost anything that's controversial on Twitter, I took a bit of a battering.

 

heh_archival_material

We've recently added date filters for radars to the StatsBombIQ platform, and Zlatan's Manchester United season is a fantastic case study for a boring old stats concept called "reversion to the mean."

Applying the concept to Zlatan, despite the fact that he scored few goals for United in the first three months of the season, I was predicting that his future output would revert toward the mean expected output, and he'd start scoring a lot of goals.

The first image below is his actual output vs predicted output from the start of the season until November 1st.

 

zlatan_through_oct31

The formats here are slightly different, but from a stats perspective, my contention was that his scoring output was going to move toward to his expected goals (xG) and expected assists (xA) at some point in the future.

Here is Zlatan's production from November 1st onward, the left side representing real world output, and the right side containing the xG info.

 

zlatan_nov1_onward

So from November onward, Zlatan actually outperformed his xG numbers by scoring more goals than expected. As my colleague DOCTOR Kwiatkowski might say, "Welcome to the world of averages and variance!"

The final Zlatan radars below are his output for the full season, which was unfortunately cut short by a brutal cruciate ligament tear.

 

zlatan_full_manunited_season

And BEHOLD, actual production and expected production ended up being very similar to each other, which was what I was suggesting would happen in the first place.

Now this happens in football all the time. A hot scoring streak that isn't backed by high xG numbers should not be expected to continue indefinitely. On the flip side, players with strong output like Zlatan above might be very good candidates for a discount transfer move, assuming you can't find obvious flaws in their game.

We actually had a situation like this happen at Brentford with regard to Alan Judge. Coming into the 15-16 season, our group really liked him. He had a great defensive work rate, some very good assist numbers, and he was pretty good with the ball.

On the other hand, by midseason, he was viewed as Brentford's only really good player. The reason for this can be seen in his shot maps.

judge_shot_map

In an amazing piece of serendipity, the point that I pulled Judge's shots for a shot location presentation I was giving was within two shots of his previous year's output. One of the things I wanted to talk about was yes, Judge was playing very well, but don't expect that level of output to continue. There was also a subtext there of, if he didn't want to sign an extension and good offers came in, maybe we should consider selling him.

The cool part about the Judge shot maps is they cut through a lot of the usual arguments you get into about player over/under performance. This was in a player

  • in the same team
  • in the same league
  • with mostly similar teammates
  • only one year older
  • With IDENTICAL SHOT QUALITY from similar locations overall

And yet one season he scored three goals and the next he scored 10 + 2 penalties, which was completely changing how everyone thought about the player, including our own club personnel.

Unfortunately, shortly after I gave the presentation, Judge suffered a horrible leg break and hasn't played since, so the concern about a reversion was replaced with an entirely different set of concerns.

In practical terms, reversion to the mean combined with not all shots being equal is exactly why we moved from using actual output to analyse players and started to use expected output. Both of the examples above are practical use cases that happen thousands of times across football every year, and when used correctly, stats help you see likely future performance far more clearly than you ever would via traditional methods.

Ted Knutson

@mixedknuts

ted@statsbombservices.com

StatsBomb Podcast: Inside Football, Ted Knutson Interview

[soundcloud url="https://api.soundcloud.com/tracks/328332513" params="auto_play=false&hide_related=false&show_comments=true&show_user=true&show_reposts=false&visual=true" width="100%" height="450" iframe="true" /] Ted Knutson talks about his experiences and ideas around football and analytics both inside clubs and during his new venture, StatsBomb Services (apologies for slight sound issues in the first 10 minutes, it clears up after) Downloadable on the soundcloud link and also available on iTunes, subscribe HERE Thanks!

Why We Need Positional Data

23 April 2017. El Clásico. Real were one man down and losing against one of the best teams in the world, with less than 15 minutes to go. The match seemed decided. But then, Real equalized.

Looking at the usually tracked events will paint a rather boring picture of the goal: Kroos passes to Marcelo, who crosses to James, who scores. But how did James get in such a great position to shoot from, and who allowed it? We can’t say.

Continue reading "Why We Need Positional Data"

West Ham: Better Expected?

lightningbolts Despite finishing eleventh, West Ham endured a pretty miserable season. The only real highlight was killing off the last 3% of Tottenham’s title challenge by beating them 1-0. A stream of transfers failed to impact the first team, some weird numerical skews killed their chances early on and the question of whether Slaven Bilic was the right man for the job started to linger. He had elicited slight structural improvements in performance in his first season and got a tidy bounce from positive variance. A string of great results against big teams away from home, in which West Ham took early leads and fended off the cavalry, were the bedrock of a seventh place finish and fewer defeats than Man Utd and Man City. Season two was very much a return to prior and lesser form. Broadly West Ham are a reliable outfit. In eight of the last ten Premier League seasons they have participated in they have scored 40-something goals. In seven of those seasons they have landed between 40 and 51 points. One time they bounced forward (2015-16, 65 goals, 62 points), one time they got relegated (2010-11, 33 points, 20th). Is this good enough though? What should West Ham be aiming for? Stadium, revenue, an opportunity? The move to the Olympic Stadium is the first aspect of the club that gives them a huge opportunity to transcend from the mid-table and aspire to more. Although attendances this season were often less than reported, the new ground has the potential to add 20,000 or more on top of the 35,000 that used to pack the Boleyn Ground. Even allowing for discounted seating in less appealing fixtures, that’s a huge jump in income. And that could move West Ham into a category of their own. The TV money jump helps everyone, but West Ham's latest (2015-16) revenues placed them seventh in the league with income around two thirds that of Tottenham. Their London rivals’ spell in the Champions League and general success will move them forward again, but adding extra match day income can put daylight between West Ham and the other mid tier clubs; Everton, Southampton, a returning Newcastle and others. They also hold the added appeal of being a London destination for potential transfers. Overall it’s an appealing structure, and they appear as well set as any time in their recent history, but really, and this is the kick: they should be doing better than they are. Metrics Seventh was slightly flattering in 2015-16 and metrics pegged them as somewhere around the eighth to tenth best team in the league. Seventeen points vanished last season but the underlying basis of this only took a comparatively small step back. Expected goals pegged them around tenth to thirteenth and they finished eleventh. west ham xgtime   The simple tale is thus: West Ham during Bilic’s reign, and before, have projected as a mid table outfit, which is more or less what they were under Sam Allardyce. In 2015-16 they got the breaks and landed high in the table, in 2016-17 they didn’t get the breaks and eventually lugged their way up into the midfield. The difference between Allardyce and Bilic in this regard was that Allardyce was consistent in defying relatively mediocre metrics to land safe, primarily through overshooting against defensive expectation. Each of the last three seasons has seen a big focus in attack on heading the ball--to be expected for an Allardyce team with Andy Carroll in the ranks but it has continued with Bilic. A third of expected goals generated in 2014-15 were via the headed route, and a quarter in each of Bilic's seasons, all compared to a league average of about 17 to 18%. *As an aside/curio, Michail Antonio scored six headers in the first 12 league games of the season (to add to 6 more from the back half of 2015-16), then only managed seven headed efforts in total for the remaining 17 starts he made, none of which landed on target.  I guess teams started to mark him. Bilic has had two seasons of high variance, one positive, another the opposite and the staid control that Allardyce inevitably brought has been replaced by a more unstable outlook. Formation indecision, soft centre Part of the problem for the team in 2016-17 was an inability to settle on a formation. West Ham finished the season with a run of games playing three at the back, a basis that they had previously tried and ultimately abandoned after their very slow start. Perhaps Bilic was unsure how to set up his team to get the best out of them? They were uniformly terrible against the top six and went 1-2-9 with the Tottenham result the only victory. They played an even six games apiece with a back three and a back four. With a back three they got steamrollered at home 0-4 by Liverpool and 1-5 by Arsenal, with a back four, Man City, Chelsea and Man Utd all arrived and won, though with less dominating shot profiles. Nine times across the season, Bilic switched between the three and the four but results remained erratic, with no great overarching pattern emerging, perhaps until the end. But if we keep digging, we find they achieved eight clean sheets from just 16 games with the three centre backs (compared to two from 22 with four at the back), and against their peers conceded just four goals total in ten games. Now this begs the question: does this mean Pablo Zabaleta’s aging legs will be utilised at wing back? Or will the formation changes continue? The three has become fashionable in the league once more, in the wake of Antonio Conte’s usage, but West Ham had tried it to little avail on three occasions in 2015-16. Overall Bilic’s team has struggled to create an identity, and his relentless tweaking has not helped here. Regardless of formation, it seems the defence wasn’t always in step. Only Sunderland conceded more chances than West Ham from logged completed throughballs--25 to West Ham’s 18--and both teams conceded a league high seven times from such opportunities. These are relatively scarce events and liable to fluctuate but nonetheless it represented double the volume of 2015-16 and a headscratcher for their manager. Retained existence in the Premier League will always be the first target, and last season's early season scares showed that they aren't immune from that yet, but much more should be the aim. What factors are hindering that progress? Transfers and continuity The specific performance conditions that Allardyce effected felt like they had a ceiling, and moving on from him was a positive move. Bilic’s first season indicated that he might have been a good appointment, and he is still carrying just enough kudos to justify the continuity of retaining him into 2017-18, but that doesn’t get to the crux of the issue. The club has failed to progress on the field and one of the primary issues here has been its short sighted use of the transfer market. Until Dimitri Payet forced through a £25m transfer back to his homeland in January--for what were rumoured to be “non-football” reasons--James Tomkins’ £10m move to Crystal Palace in the preceding summer was a notable outlier. West Ham are not a selling club. They are not a selling club insofar their players are rarely coveted by larger clubs. Since returning to the Premier League in 2012-13, they have consistently spent at a deficit, but have rarely pulled in any more than token income from turning over their squad. I hammered their 2016-17 transfer policy before, but the truth is it goes back a lot further and while the team maintains its position it’s unlikely to be classed as a problem. However, the team lacks continuity. Pablo Zabaleta’s swift arrival is endemic of the lack of foresight that has afflicted West Ham’s recruitment in recent years. At 32 and past his best in a high energy position, Zabaleta can fill a gap, but is unlikely to move the needle. Often mid-tier clubs are seduced by the profile of decorated players moving out of larger teams and see them as worth a gamble. In moderation, such players can give a fillip to a younger squad but when the team’s last two signings in January were a 33 year old centre back (José Fonte) on a two and a half year deal and a 29 year old winger (Robert Snodgrass)--another likely energetic role--on a three and a half year deal? It’s an unfortunate trend. Talented players, sure, but at entirely the wrong end of the age curve, with zero resale value and potentially about to fall off a performance cliff. The idea that Bilic staying gives continuity is undermined by such a short sighted transfer strategy. And the blueprint for what the club should look to be doing exists one hundred miles down the M3 in sunny Southampton. Here’s a club that has such a strong structure in place that their down year was a point better that West Ham’s reversion to the norm, and underlying metrics were still sound enough to rank them in the top seven for expected goals for the fourth consecutive year. A tough to measure blend of Claude Puel’s methods and variance meant they bottomed out, but their bottom is significantly higher than West Ham’s right now, and their background structure is built to survive not just changes in playing staff but managerial moves too. Their player development and identification means they can comfortably rejig their team while supplying the rich with new toys, while maintaining a solid position. With Puel gone, they are a positive managerial appointment away from again challenging the outskirts of the top four, and continue to punch well above their weight at exactly the time building a club while remaining in the league has a huge upside. So Bilic continues... With Rory Campbell at the club and analytically minded, and Michael Caley having previously been consulted, it's not as if West Ham have zero smarts in this direction, its just there is precious little evidence that more recent Bilic era recruitment is switched on, at all. Perhaps meandering around in mid-table is enough for the club's hierarchy, but David Sullivan and David Gold are fans too, and they're currently missing out on maximising the return on their investments by operating a reactive recruitment model. West Ham's future can be much more, but only if the influencers can see the bigger picture.   @jair1970

Tinker, Tailor, Mould a Side: Squad Rotation in the EPL

Introduction

One of the key features of Chelsea’s title winning season was the consistency of their starting lineups. After the 3-0 thrashing by Arsenal in September, Conte switched to a 3-4-3 formation and Chelsea embarked on a 13-match winning streak in the league that ultimately propelled them to the title. The foundation of this formation – Luiz, Cahill and Azpilicueta – started each of the next 32 games, and the wing-backs, Moses and Alonso, missed only three between them.

Such consistency is partly due to luck with injuries and suspensions, but Conte also resisted the temptation to tinker with his team. Other managers opted to ring the changes, for tactical purposes or to rest players. In the closing weeks of the season Mourinho was compelled to defend his rotation policy, citing fixture congestion and the need to maximize his chances of Europa League success. However, frequent changes to United’s starting lineup were a feature of their entire season not just the final few months.

In this article I’m going to take a detailed look at how EPL clubs utilized their squads throughout the season. I’ll compare the rate at which managers ‘rotated’ their teams (which I define simply as the number of changes made to their starting lineup) and the number of players they used in doing so. I’ll then investigate some of the factors that may have influenced a manager’s decision to fiddle with his starting lineup. Finally I’ll discuss whether rotation had an impact on results.

Squad Rotation

Let’s start with a look at squad size and rotation. Figure 1 plots the average number of changes made to their starting lineup against the total number of players used by each EPL club last season.

Clubs on the left-hand side of the plot preferred to maintain the same starting lineup, changing about one player per match. Those plotted towards the right of the plot varied their team more frequently. The vertical axis measures effective squad size – the number of players that started at least one EPL match [1]. Teams that are plotted towards the bottom of the plot picked their lineups from a relatively small group of players, those plotted nearer the top chose them from a larger pool.

Rotation_SquadSize

Figure 1: Squad rotation (average number of changes made to the starting lineup) versus effective squad size (number of players that started at least one EPL match) for all EPL clubs in 2016/17. Uses data provided by Stratagem Technologies.

Both quantities plotted in Figure 1 are important. A manager could adopt a highly structured rotation policy in which three players are changed in each match but are chosen from a small squad of only 14 players; this club would appear in the bottom right of the plot.

A manager that was struggling to find his best eleven might make the same number of changes per match but from a much larger pool of players; this club would appear near the top right of the plot. On average, EPL clubs made around two changes per match to their starting lineups, from an effective squad size of twenty-five players. As you might expect, there is clearly a relationship between squad size and rotation: the more frequently that a club rotated the greater the number of players they tended to use. West Brom, Chelsea, Burnley and Liverpool, who made just over 1 change per game, fielded the most consistent lineups. Along with Spurs, they also used the fewest numbers of players [2].

At the other end of the scale there is the two Manchester Clubs – both of whom made over three changes per game to their starting lineup – followed by Southampton, Middlesbrough, Swansea and Sunderland. Man Utd and Sunderland, along with West Ham and Hull, all used at least 28 players over the season (admittedly United started 5 players for the first time in their last game of the season).

So there was quite a broad spectrum of squad management styles in the EPL this season with some clubs rotating more than twice as fast as others, and using nearly 50% more players. Why is this? To what degree are team changes enforced or by choice? I’ll now review some of the factors that may have influenced team selection.

Injuries

Injuries and suspensions will have forced managers to make changes to the team. According to physioroom.com, Sunderland suffered the most injuries of all EPL clubs last season, 81 in total [3], with Man United, West Ham and Watford all receiving over 70. Chelsea, West Brom and Burnley were much luckier, suffering about half as many. Liverpool were the black sheep: the only other team to suffer over 70 injuries, but still one of the most consistent starting lineups. I haven’t found data listing the total number of players suspended at each club last season, but Man City, Sunderland, Hull, West Ham and Watford all received at least four red cards, whereas Liverpool, Chelsea, Spurs, Palace and West Brom received none.

In general, there is a weak correlation between both Transfermarkt’s ‘fair play’ score and physioroom’s injury counts, and the squad rotation metric used in Figure 1. This suggests that while injuries and suspensions will have contributed to squad rotation, they were not the main driver.

Fixture Volume

Fixture volume over all competitions seems to have influenced some club’s selection decisions. EPL teams played an average of 47 matches this season (which is exactly the number that Chelsea played); Man United played 64 – over a third more – and Man City 56. Generally speaking, teams that played more than 50 matches tended to rotate their league teams more frequently than those that played less, although Sunderland and Middlesbrough both played only 43 matches. European competition is one of the biggest sources of additional matches; in a previous blog I’ve demonstrated that playing in Europe does affect domestic results in the EPL.

A Settled Defence

A key feature of the clubs that rotated the least was a settled defence. Throughout the season Burnley and Chelsea fielded only 6 unique combinations of players in defence, and their preferred defence started more than 25 league matches. In contrast, most EPL teams tried more than 15 different combinations of players in defence, with their most frequent combination typically starting around 12 matches. The teams that rotated the most – those towards right of Figure 1 – never really established a first-choice defence.

The following plots emphasize this point. They show the starting lineups of Burnley and Man City in each of their 38 league matches last season. A dot indicates that a player started the match, with blue dots indicating players that were retained in the starting lineup and red dots showing those that were brought into the starting team. The result of each game is given along the bottom. Similar graphics for all EPL teams can be found here.

The difference between the selections in defense is striking. Both clubs used seven defenders over the course of the season. However, while Burnley’s first-choice back four is obvious, City’s certainly is not. Over the course of the season they tried 21 different combinations of players in defence, which is well over half the total number of unique ways you can select 4 players from 7 [4]. City's most frequent combination in defence was Kolarov, Otamendi, Sagna and Clichy; they started a grand total of 4 matches together.

Burnley_lineups Manchester City_lineups

Indecision  

It took some managers several matches at the start of the season to identify the core players around which their team could be constructed. Others took much longer decide on their strongest lineup, and a few never did.

For example, David Moyes never really figured out his best team, as the plot below demonstrates. He deployed 36 unique combinations of players during the season (nearly double that of Chelsea), and there was a lack of consistency in defence and midfield, both in terms of personnel and formation. Jose Mourinho also tried a large number of different combinations in every position, particularly in the second half of the season. While United's rotation frequency certainly increased in the last couple of months of the season, they were already rotating at over 3 players per game before Christmas.

Sunderland_lineups Manchester United_lineups

Does rotation matter?

Is there any evidence that rapid squad rotation influences results? This is a tricky question to answer because we don’t know how a team would have performed had they been more or less consistent in their team selection. Periods of high rotation do seem to have coincided with worse results for many teams (West Ham, Watford, Crystal Palace and Swansea, to name a few). However, there is a bit of a chicken-and-egg issue: poor results may compel a manager to change his team until he finds a winning formula.

I find there to be no significant relationship between squad rotation and final league position last season. However I would hazard the suggestion that the majority of teams that prioritized stability and a tight-knit squad – those nearest the bottom left corner of Figure 1 – all had successful seasons by their own standard. Crystal Palace are perhaps the exception, but the rate at which they varied their starting lineup dropped significantly (from 2 changes per game to 1) in the second half of the season once Sam Allardyce took charge.

Similarly, those clubs that rotated frequently from a big squad generally had a disappointing year relative to pre-season expectations: City failed to mount a sustained title challenge, United finished sixth, and Hull, Swansea, West Ham, Middlesbrough and Sunderland were either relegated or flirted with relegation.

Perhaps this is just postdiction, but I think it warrants further investigation. It would be interesting to establish whether the performance of a team tends to decline towards the end of a long season if players are not rested. Are big squads problematic if managers are forced to rotate simply to keep his players happy? Does rotation interrupt momentum?

No Europe and a lack of injuries have helped, but the last two EPL seasons have been won by clubs that identified their best 11 players and stuck with them; tailoring and not tinkering. As clubs recruit over the summer we’ll see whether this is a theme that has started to resonate.

Lineup graphics for all EPL teams can be found on my blog here

[1]  I’ve investigated other measures of squad size, in particular counting the number of players that started at least 2 or 3 games; none of the conclusions would change significantly.

[2] Note also that Chelsea used three players for the first time in their second-to-last game, when they had already won the league

[3] Injuries are counted from the first weekend of the season. It’s worth on noting that this count includes injuries to squad players who weren’t necessarily in the starting lineup.

[4] Furthermore, City also experimented with Fernandinho or Navas as right full backs, so arguably their defence came from an even bigger pool, and was even more erratically selected.