The Week in Stats: David Silva’s teammates are letting him down

This week, we look at the players who are significantly over- and under-performing in terms of their expected assists numbers.

Expected goals (xG) and expected assists (xA) provide us with an easy way to identify both the players who are being failed by their teammates and those who are themselves letting the side down.

This is because xG tells us how many goals a player would have scored on average from the opportunities he’s had, while xA lets us know how many assists a player would typically have earned from the chances he’s created for his teammates.

So subtracting the actual number of assists a player has from their xA totals allows us to see which of them are significantly over- and under-performing in this regard. We’ll start with those under-performers, meaning the players who haven’t achieved the numbers of assists the underlying stats suggest they’ve deserved.

The creative players who’ve been most let down by their teammates in each of the big leagues are David Silva, Hoffenheim’s Nico Schulz, Denis Cheryshev at Valencia and Camillo Ciano of Serie A’s Frosinone.

Manchester City’s Silva has three assists to his name in the Premier League but has created 6.98 xA of chances. That amounts to a league-high under-performance of 3.98. Meanwhile, Joe Ralls of Cardiff has presented his team with 2.61 xA of opportunities but still doesn’t have a single league assist to his name.

Over in Spain, Russian forward Cheryshev’s numbers deserve to be much better. On average he would have had three times as many assists than the two he currently holds, having created 6.07 xA. In fact, that xA total has only been bettered in La Liga by Pablo Sarabia of Sevilla and a certain Lionel Messi, whereas 43 players presently have more league assists than Cheryshev.

Portuguese striker Andre Silva is also being let down by his teammates’ finishing. Nonetheless, after finding it hard to justify the price-tag last season following his €38 million switch from Porto to AC Milan, he’s thriving this term after moving to Sevilla on loan.

Last year Silva didn’t score his first league goal until March, whereas he already has nine goals to his name in La Liga, with none of them coming from the penalty spot. But as you can see from the chart above, he still doesn’t have even a solitary league assist this season despite laying on 3.61 xA of chances for his team.

The Serie A list highlights a player to keep an eye on. If, as is almost universally predicted, Frosinone end up being relegated, it seems very likely that Ciano will move to another club in the Italian top flight. His 4.27 xA puts him in the top 10 of Serie A providers, although that good work has earned him just one assist so far.

None of these players, however, have been let down as much as Schulz in the Bundesliga. The Hoffenheim wing-back, who made his debut for Germany in October, has just two assists from the 6.57 xA of chances he’s supplied. That works out at a European-high deficit of 4.57.

Next, we’ll move on to look at the xA over-achievers: The players who’ve racked up considerably more assists than their underlying numbers suggest they typically would have.

The presence of three Borussia Dortmund players — Lukasz Piszczek, Jadon Sancho and Raphael Guerreiro — in the top five Bundesliga xA over-achievers perhaps shouldn’t come as too much of a surprise.

As Ted Knutson reminded us on StatsBomb back in October:

"“Lucien Favre has a long history of high performance in the table with his teams spoofing how good xG models expect them to be. He’s done this consistently enough at Gladbach, then Nice, and now Dortmund that I believe his style of play basically exists in all the holes of naive xG models.”"

So if anyone else were in the dugout at Dortmund, then we’d expect those xA numbers to revert to the mean before the end of the season. With Favre in charge, we can’t be so sure.

What we can say with much more certainty, though, is that Celta Vigo are in all kinds of trouble. Unlike Dortmund, they don’t have a magician in the coach’s seat — indeed, they’ve sacked two managers since the start of May.

The Galician club are currently 16th in the table, just a point above the relegation zone. But all the main advanced metrics, including xA as we can see above, point to them being even worse than that would suggest.

Just as David Junca, Brais Mendez and Maxi Gomez are lucky to have 14 assists between them, Celta are fortunate not be even further down the table. Gomez is the most likely of the three to drop off, as he currently has five assists from just 2.03 xA of chances created.

Meanwhile, in Italy the over-performance of Genoa’s Domenico Criscito is also unlikely to continue. In his case that’s because of the departure to AC Milan of Krzysztof Piatek, for whom Criscito provided half of his league assists.