Saturday 23 December 2017

Influential xG & xA Team Players

Expected goals and expected assists are now becoming an established part of player performance stats and rather than post column after column of boring and indigestible numbers, often to two decimal points, I've been presenting the data as a visual.

It seemed logical to plot the xG/90 against the xA/90 with a minimum cutoff for minutes played to mitigate the intrusion of outlandish outliers.

Here's one of my plots for the Premier League, earlier in the season.

Players appearing towards the top left are the league's more prolific providers of an opportunity, while bottom right is populated with players who more often latch onto the final decisive pass.

Players who had been doing quite a bit of both turn up in the top right region of the plot.

It's immediately obvious that Manchester City dominate the plot, as you might expect from their near perfect start to the season and as a record of the league's most prolific attacking contributors, the plot does it's job.

However, while the prominent multiple players from the same teams, notably City and Arsenal are undoubtedly fine players, their individual performance indicators are perhaps made slightly easier to achieve given the quality of their teammates.

De Bruyne's precise passing is also feeding into the xG of his teammates, as are their intelligent runs creating opportunities for him to bolster his xA.

So as a tweak to my original plots, I've now factored in the overall xG and xA/90 of the team for which each player plies his trade. This results in many of the Manchester City players falling back into the pack.

The individual players are still creating and attempting to convert chances at similar rates to the original plot, but such is City's commitment to attacking play (they are averaging upwards of 2.6 NP xG per game) and such is their depth of creative and attacking talent, that they don't have one particularly stand out performer.

Conversely, Peter Crouch, who would be unlikely to feature prominently in a plot that merely quantified his raw xG and xA/90 contribution, shows up as a hugely influential contributor to Stoke's offensively tepid, overall attack once we factor in the Potters' overall team NPxG/90 of barely 1.0.

As an example, Aguero's combined xG/90 & xA/90 of 1.3 from an overall Manchester City combined rate of nearly 5 xG & xA/90, is arguably less influential and more readily replaced from within than is Crouch's combined 0.6 against Stoke's puny overall 1.8 xG+xA/90.

Whilst the heavyweights from Manchester City will undoubtedly take the plaudits in May, it is perhaps the likes of Crouch, Murray, Austin, Carroll and Gross who are striving and greatly contributing the most to keep their lesser sides afloat who also deserve a mention and their own viz.

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