A statistical look at Chelsea’s new signings

Chelsea have made a major impact in the 2020 summer transfer window by signing Hakim Ziyech, Timo Werner, Ben Chilwell, Malang Sarr, Thiago Silva, and Kai Havertz. Out of the signings, Ziyech, Werner, Chilwell, Silva, and Havertz will be starters for the club in the 2020/20201 season, and each is expected to have a large impact towards improving the squad. These lofty expectations have brought a level of excitement and hysteria that has not been paralleled since the infamous 2003/2004 summer transfer window, and fans may be thinking the new signings will take the club to another league title in 2020/2021.

Last season saw young and promising players take their final step into becoming a first-team player, and each showed capability to handle the responsibilities of playing for Chelsea. Particularly, Christian Pulisic, Mason Mount, Mateo Kovacic, Reece James, and Tammy Abraham (who scored 15 league goals, the most for a striker at CFC since the combative and fiery Diego Costa). The new signings will have stiff competition for a starting XI place, but logic would lead one to believe that the new signings will initially be in the starting XI because of the amount of money spent to bring each to the club.

Stats, Glorious Stats

Yet, how do the new signings compare on a statistical level? How much of an improvement, if any, are the new signings? To answer this, I focused and analysed the league stats for current and incoming players from their respective leagues abroad last season. I restricted this analysis to the offensive signings in Ziyech, Werner, and Havertz. I analyzed goals, assists, Gp90, Ap90, G+Ap90, shots per game, key passes per game, completed pass percentage, completed crosses per game, and for midfielders, tackles and interceptions per game.

Hakim Ziyech had superior stats in goals and assists from the 2019/2020 league season when compared to any of the wingers at Chelsea FC. Particularly, Ziyech almost doubled the assists tally from Willian, who was Chelsea’s leader in assists from last season with 7 (Ziyech had 13 assists last season in the Eredevisie). Willian led all Chelsea wingers with 9 goals and 7 assists, which is fair output, but significantly less than Ziyech’s 6 goals and 13 assists.

One of Chelsea's post winter signings, Hakim Ziyech, outshines current squad when it comes to comparing goals and assists by Chelsea wingers.
Goals and assists by wingers in league matches across the Chelsea squad.

Ziyech not only produced the most assists, but he produced assists at a spectacular rate of 123.6 minutes per assists. Another metric to look at is goals and assists per 90 minutes, and once again, the magician of Amsterdam did not fail to deliver. Ziyech trailed only Pulisic in Gp90, but Ziyech is a massive improvement over the current squad options with an Ap90 of 0.73, and the next closest winger in the squad is CHO with an Ap90 of 0.52.

The newest signing's, Pulisic and Ziyech are top of the class when it comes to comparing goals and assists in 2019-2020.
Graph of Gp90 and Ap90 by Wingers in 2019/2020 League Matches

Ziyech also took more shots (4.2 shots per game), had more key passes (3.7 per game), dribbles (2.6 dribbles per game) and completed more crosses (2.3 crosses per game) than any winger in Chelsea’s squad last season.

Clearly demonstrated the need for Chelsea to bring in Ziyech as a part of the new group of signings with their cross and key pass ratios.
Shots per game and Completed Crosses per Game by Wingers and Key Passes and Dribbles per game by Wingers

Timo Werner also seemingly represents a drastic upgrade over any of the forwards in the squad from last season. This can be qualified by the incredible goal and assist output that Werner was able to manage with RB Leipzig last season. Werner finished with 28 goals and 8 assists in 34 appearances in the Bundesliga, which is almost double Tammy’s output of 15 goals, which led the squad last season. Werner also produced goals at the fastest rate of any forwards analyzed, with 0.90 Gp90 and Werner’s 0.26 Ap90 trailed only Batshuayi (Batshuayi only registered 226 league minutes, so this is a faulty conclusion because the sample size on is too small to make accurate predictions and inferences).

One of the signing's of the summer, Timo Werner eclipses Chelsea's attackers when it comes to goals and assists.
Combined graphs for “Goals and Assists by Forwards” and Gp90 and Ap90 by Forwards”

Additionally, Werner will also provide more opportunities for the squad to get into better attacking areas, as Werner is a clear upgrade on any of the forwards from last season in terms of completed dribbles and shots per game. Werner also provided 0.5 completed crosses per game, 1.6 key passes per game, and a 75.6 pass completion percentage.

Once again, one of the new signings stands out when it comes to shots and dribbles per game.
Graph for Shots and Dribbles per game by Forwards in 2019/2020 League Matches

Finally, let’s take a look at the newest signing in Kai Havertz, who is also the most expensive of any of the new signings. The German wonderkid provided more goals and assists than any midfielder in Chelsea’s squad last season with 12 goals and 6 assists in 30 appearances. Havertz also produced goals at the fastest rate, and only trailed Ross Barkley in Ap90 and Minutes per Assist. Havertz played nearly 2.25 times the number of minutes as Ross Barkley though, so sample size may help to explain why Ross leads in Ap90 and Minutes per Assist.

Havertz has the potential to be one of the worlds best. Top individual to be a part of the summer signings and Havertz's goals and assists ratio shows why.
Combined graphs for “Goals and Assists by Midfielders in 2019/2020 League Matches” and “Goals and Assists per 90 Mins by Midfielders in 2019/2020 League Matches

Havertz registered 2.0 shots per game, which only trailed Mason Mount’s 2.1 shots per game from last season. Havertz also provided more key passes and dribbles per game than most competing midfielders, with 2.0 key passes and 1.9 dribbles per game. Only Kovacic registered more dribbles with 2.5 per game. In terms of statistical analysis, Havertz looks outstanding.

Outshone in some aspects by Chelsea POTY Kovacic, Havertz stands out compared to the rest. A much needed signing when it comes to passes and dribbles.
Graph of Passes and Dribbles per Game

One of the only aspects that Havertz does not stand out relative to the competition is in tackles and interceptions per game, which is to be expected, as Havertz was used further forward on the pitch at Leverkusen.

In the midfield, Chelsea have defensively sound players. Havertz was a signing, purchased for his attacking ability as his tackling stats show.
Graph titled Tackles and Interceptions per Game by Midfielders in 2019/2020 League Matches

One simple criticism of the above analysis is the typical argument that “the Premier League offers a higher level of competition, and the statistics cannot be expected to remain the same in a more difficult league with greater level of opposition talent.” To appease this argument, I have reduced the statistics of Ziyech, Werner, and Havertz by 25% and the results for each player are displayed below.

Ziyech stats with “Premier League Tax”
  • 4.5 Goals
  • 9.75 assists
  • 0.255 Gp90, 0.5475 Ap90, 0.8025 G+Ap90
  • 3.15 Shots per game
  • 2.775 key passes per game
  • 1.95 dribbles per game
  • 1.725 completed crosses per game
Werner stats with “Premier League Tax”
  • 21 goals
  • 6 assists
  • 0.675 Gp90, 0.195 Ap90, 0.87 G+Ap90
  • 2.70 shots per game
  • 1.2 key passes per game
  • 1.275 dribbles per game
  • 0.375 crosses per game
Havertz stats with “Premier League Tax”
  • 9 goals
  • 4.5 assists
  • 0.33 Gp90, 0.165 Ap90, 0.495 G+Ap90
  • 1.5 shots per game
  • 1.5 key passes per game
  • 1.425 dribbles per game
  • 0.15 crosses per game

Even with these reductions in stats, to appease the narrative that the Premier League will create decreased stats for incoming players, it is still clear that each incoming player represents an objective improvement over the players from last season. There is no reason, from a statistical standpoint, to fear a large drop-off in stats and player performance for the new players. Each will likely be a drastic improvement from last season, add new dimensions to the attack, and take Chelsea FC to greater heights and have them competing for top honors next season.

Written by: Travis (@crossroads_cfc)

Edited by Jai Mcintosh & Rob Pratley


One thought on “A statistical look at Chelsea’s new signings

  1. Wonderful analysis.I fear for HERVATZ, He is physically not there and might struggle with injury in premier league aggressive style

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