Mesut Özil’s record-breaking season at Arsenal is getting plenty of attention. I’ve already suggested that last season was, at least in the time he played, an even better one. But I think it’s useful to look at a few more statistics that may give greater clarity to his role.
Soccer is a dynamic game, and every player’s actions affect every other player’s actions. Moreover, when one guy plays, there’s another guy – or several – sitting on the bench. So analysts have to figure out the net effect on the whole team’s performance of apparent changes in a single player’s performance. In principle, this net effect is the only thing that matters, except perhaps to the player’s ego.
There is no doubt that Özil has been exceptionally productive this season. Part of the reason for this is incredibly simple: he’s played more minutes. Özil is on track to play 3,178 minutes in the league, which is almost two thirds more than he played last season. As one of the most talented attackers in England, it’s not surprising that he should post impressive numbers when he plays more.
But his rate of production, at least by one measure, is also increasing. Below is a list of Arsenal’s top 10 providers of assists for shots – whether they turned into goals or not – per 90 minutes for the past three seasons (note that this analysis doesn’t consider the quality of the shots following each player’s assists):
Özil was always on top, but he’s risen to a new level this season. No one in the past six seasons of the Premier League has played at least 360 minutes and topped 4.3 shot assists per 90 minutes. Only Carlos Tévez was above 4.0, with 4.1 per 90 minutes in 637 minutes for Manchester City in 2011-12.
The question is whether anyone else at Arsenal has dropped off. The club’s overall shot assists per 90 minutes have risen by about as much as Özil’s, so it’s possible that his boost in performance has been completely additive. But some of the most prolific shot assisters from prior seasons have declined, notably Alexis Sánchez, Aaron Ramsey, and Olivier Giroud. And some other guys are playing fewer minutes, because Özil is almost always on the field.
The result of these changes is visible in the last line of the table above. It’s the Herfindahl-Hirschman Index of concentration for Arsenal’s shot assists. After being fairly steady for the past two seasons, the index has jumped significantly. In fact, no team has had such concentrated shot assists in the past six seasons. Only Hazard-reliant Chelsea has come close, with just under 0.15 this season.
So a major risk for Arsenal is an injury to Özil. They’re putting all their eggs into his one basket to a historic degree. Given Özil’s displays of superb skill, I’m sure most neutrals will be hoping he stays healthy, too. But for the opposition, it’s pretty clear that stopping him would put a big dent in Arsenal’s attack.
All that said, Özil still isn’t Arsenal’s most important player – or even attacker – this season. Going by Shapley values, the club’s most crucial attacker, until his injury, was Sánchez. The Chilean’s own shot assists had fallen, but he was often the one drawing defenders and making space for Özil to work his magic, then taking the shots after all those assists. Alexis giveth, too.