It has been confirmed that Chelsea left wingback Ben Chilwell would be out for at least the next six weeks due to injury, and it is only after then that the decision on whether to do surgery on his ACL would be made. This has caused some questions and worry in the fanbase as to where the Blues should go from here because Chilwell had been first choice left back up until his injury.
It is not outrageous to be concerned that your first choice left wing back is out to injury, however the discourse around his definite replacement for the role, Marcos Alonso, is as though Alonso did not start the first six games of the season for Chelsea, playing very well. Truth be told, the level Alonso and Chilwell are playing at are not as far apart as many would make you believe.
Chilwell got his chance in the starting lineup after Chelsea’s loss to Italian giants Juventus. Chilwell took his chance, and has played very well, earning him subsequent starts and even seeing him score in four consecutive games in all competitions.
I looked at 23 metrics for the two left wing backs, to compare the performances between the two. This comparison was applicable and almost straightforward because both players have played and started the same number of games in the same position in the league for Chelsea this season, though necessary context is still applied. The categories cover almost all phases of play, including actions in and out of possession as well as performances in both boxes.
Defensive actions
Alonso (3.6) makes more tackles and interceptions per game compared to Chilwell (2.0), though Chilwell makes more pressures per game at 15.7 compared to Alonso’s 12.2. Chilwell is also better at pressing, winning 33-percent of his pressures compared to 25-percent of Alonso’s. Alonso (0.8) also gets dribbled past slightly more than Chilwell (0.5) per game. Chilwell wins slightly more ground duels, 4.3 to Alonso’s 4, however he does it at a much higher rate, 58-percent success to Alonso’s 48-percent. This is on par with what we can expect from these two. Chilwell is more athletic than Alonso, and therefore faster, probably explaining why the Englishman makes more pressures and wins more ground duels.
Interestingly they both win the same volume of aerial duels (1.2) per game, but Alonso wins his at a higher rate, 47-percent to Chilwell’s 41-percent. It is important to note that Alonso should be doing better aerially because of his height. The tackles and interceptions numbers indicate a more experienced player in Alonso, and a superb reading of the game. They have both kept the same number of clean sheets in the times they’ve started as well (four).
Passing and Ball Progression
Chilwell makes more passes per 90 than Alonso, 44.2 to Alonso’s 41.7. This is not particularly a feather on Chilwell’s cap, as Alonso does way more valuable things with the ball, more frequently, than Chilwell. Alonso makes a progressive pass* every 11.7 passes, but Chilwell makes one every 20.4 passes. That’s a big difference. Alonso also makes a pass into the final third every 13.7 passes, compared to Chilwell who makes one every 37.8 passes. Alonso makes 1.19 passes into the penalty area per 90, compared to Chilwell’s 1. This is interesting as Alonso is often touted as sucking the dynamism out of the side. Many seem to have forgotten how good the Spaniard was up until the Manchester City game.
Alonso has been doing better than his English colleague in terms of carrying the ball forward as well. Alonso and Chilwell carry the ball in general exactly 40 times per 90. However Alonso makes a progressive carry* every 6.2 carries, while Chilwell makes a progressive carry every 10.4 carries. This also means that Alonso makes more progressive carries per 90, 6.44 to Chilwell’s 3.83. Chilwell though, gets into positions to receive progressive passes more than Alonso, but not by much, receiving 5 progressive passes per 90 compared to Alonso’s 4.4.
The difference in the ball progression of these two is quite clear, and sometimes not close, which indicates that Alonso is much better at passing and progressing the ball up field, contrary to what many are claiming.
Chance creation and goal involvement
Alonso has created more chances per game, 2.0 compared to Chilwell’s 1.8. Chilwell has created one big chance, but Alonso is yet to create one. Chilwell bests Alonso in Shot-Creating Actions per 90, 3.5 to Alonso’s 2.9, however they both average the same amount of Goal-Creating Actions per 90 (0.17). Alonso has scored one goal and assisted one, Chilwell has scored three goals and assisted one.
Alonso again shows that he’s the better crosser, somewhat, averaging 1.5 completed crosses per game according to SofaScore, compared to Chilwell’s 1.2, however they both average the same accuracy (22-percent success).
It is left to you to decide which traits and metrics you want to place more value on, however if one thing is clear, it is that Chilwell and Alonso have played brilliantly this season and Alonso is not as much of a step down from Chilwell as some are portraying, in fact depending on what you’re looking for, in some cases it’s a step up. This piece is not intended to make the case that Chilwell hasn’t been as good as he’s seemed, but it’s mainly to highlight that perception is often different from reality. Chilwell’s loss is perceived as a blow to the Blues chances and crisis at left wingback, but further scrutiny shows that Alonso has been equally as good and sometimes better.
Important context to apply to those numbers is Opponents Played. Chelsea had a difficult start to the season and still came out on top of the table by Match Day six. Chelsea played four of the traditional big-6 teams in the first six weeks, including three London derbies. They won all the derbies and took seven points out of 12 available points against Arsenal, Liverpool, Manchester City and Tottenham Hotspur. Alonso played in all these matches, including being a standout performer against Liverpool, minus the mix-up with Chelsea goalkeeper Edouard Mendy leading to Liverpool’s equalizer. Alonso played the more difficult opponents of Chelsea’s first twelve games, while Chilwell has played the relatively easier six games of the twelve including Burnley, Norwich City, Newcastle United and Leicester City. Now how much better do Alonso’s numbers look?
All stats are from FBRef and SofaScore
*Progressive carries are carries/dribbles but do not include passes of the ball that move it 5 yards or more (it may be longer on some sites) in the direction of the opposition goal.
*Progressive passes, according to WyScout are passes of the ball that attempt to move the team significantly towards the opposition goal, or in simple terms, attempts to get the team closer to scoring.