We’re only two games into the current English Premier League season, so it’s way too early to make any sweeping pronouncements. (Except maybe that Chelsea’s stint in 16th place won’t last long.) But here’s one fairly safe bet: Tottenham striker Harry Kane isn’t going to replicate his 2014-15 performance.
No player in the Premier League last season scored more goals beyond our expectations than Kane.
Soccer’s analytics are fledgling, but one of the emerging metrics is Expected Goals (ExpG), a measure that tries to assign probability that a given shot will result in a goal. A tap-in from inside the six is more likely to go in than a volley from 40 yards. ExpG is an attempt to capture that difference. Throw in any number of other factors — was the shot from a header, did it come off a cross, was the weather cold or rainy? — and one can build a model that calculates probabilities for every shot type at any location. I know it’s possible because I did it.4
Last season, Kane had 19 non-penalty league goals5 on an ExpG total of 11.33. That’s a hard thing to do year after year. Unless he’s a truly elite player — and we don’t have a reason to think he is yet — he’s due for a regression.
For Kane to overachieve again, he’d have to succeed where almost everyone else has failed recently. The top 15 over-performing player seasons, based on ExpG, from the 2011-12 through 2013-14 seasons declined on average 80 percent from their over-performance the year before. These aren’t scrubs, either: Luis Suarez, Yaya Toure, Klass-Jan Huntelaar — most of those are exceptional players. Kane would have to be a once-in-a-generation talent (like Lionel Messi, who has three of the top 10 overachiever seasons of the past four years) to not regress.
| PLAYER | SEASON | TEAM | GOALS | EXPG | DIFF |
|---|---|---|---|---|---|
| L. Messi | 2012-13 | Barcelona | 42 | 23.8 | 18.2 |
| C. Ronaldo | 2014-15 | Real Madrid | 38 | 25.5 | 12.5 |
| L. Suarez | 2013-14 | Liverpool | 31 | 18.6 | 12.4 |
| L. Messi | 2014-15 | Barcelona | 38 | 27.0 | 11.0 |
| G. Bale | 2012-13 | Tottenham | 21 | 10.6 | 10.5 |
| M. Reus | 2011-12 | Borussia Monchengladbach | 18 | 8.2 | 9.8 |
| C. Immobile | 2013-14 | Torino | 22 | 12.3 | 9.8 |
| L. Messi | 2011-12 | Barcelona | 40 | 30.3 | 9.7 |
| L. Podolski | 2011-12 | FC Koln | 15 | 5.4 | 9.6 |
| C. Ronaldo | 2011-12 | Real Madrid | 34 | 24.8 | 9.3 |
| G. Higuain | 2011-12 | Real Madrid | 22 | 13.4 | 8.6 |
| K. Huntelaar | 2011-12 | Schalke 04 | 23 | 14.4 | 8.6 |
| M. Harnik | 2011-12 | Stuttgart | 17 | 8.5 | 8.5 |
| A. Greizmann | 2014-15 | Atletico Madrid | 22 | 14.2 | 7.8 |
| J. Rodriguez | 2014-15 | Real Madrid | 13 | 5.3 | 7.7 |
| H. Kane | 2014-15 | Tottenham | 19 | 11.3 | 7.7 |
| A. Sanchez | 2013-14 | Barcelona | 19 | 11.5 | 7.5 |
| J. Drmic | 2013-14 | Nuernberg | 15 | 7.8 | 7.2 |
| Y. Toure | 2013-14 | Man City | 14 | 6.8 | 7.2 |
| P. Cisse | 2011-12 | Freiburg / Newcastle | 13 | 6.0 | 7.0 |
Except his short Premier League history doesn’t suggest that he is. In 2012-13, while on loan at Norwich, he took a grand total of four shots. The next season, in 10 appearances with Tottenham, he scored three times against an ExpG of 4.44. It wasn’t until a 1-2 home defeat to Stoke in early November of last year that coach Mauricio Pochettino even made Kane a regular starter.
Kane’s regression might already be happening. Going back to the beginning of April, Kane has scored just twice over nine games. It’s a somewhat arbitrary cutoff, but it encompasses the final stretch of Premier League games after the last international break (England drew with Italy; Kane played all 90 minutes but didn’t score) and the first two games of this season. The two-goal total is below Kane’s ExpG of 2.78.
Kane’s career is made up of 20 games where Kane is almost Messi and then another 21 (albeit broken into two nearly equal sets and separated by a full year) where Kane isn’t quite even Kane.
It’s not all bad news for Spurs fans. Mean reversion doesn’t mean Kane will score eight goals below his ExpG number this season so that his performances average out like magic. He’s just likelier to score something more in line with his calculated ExpG. He’s the team’s main (and close to only) option up top, which should help. (Although there is still time in the transfer window for Spurs to bring in some help.) He should see plenty of chances, enough that his ExpG could be in the neighborhood of 156 — and 15 here is still a big number. If Kane scored 15 league goals it wouldn’t even look like much of a drop-off, even if it represented a complete regression.
CORRECTION (Aug. 21, 1:33 p.m.): An earlier version of this article included a table that misidentified the team Luis Suarez played for in 2013-14. It was Liverpool, not Barcelona.