When Thomas Tuchel arrived at Chelsea, he immediately put the squad into a 3-4-2-1 shape. There were many reasons for this. The extra centerback makes the defense much harder to break through and also makes the team much harder to counter against, both issues at the end of Frank Lampard’s tenure. Three at the back also forces the opposition to commit an extra man to the press as Chelsea plays out of the back, creating more vertical space to move the ball into quickly.
Three at the back has not come without a cost, however. This cost is primarily on the attacking end. While the 3-4-2-1 can create overloads better than most formations, it is heavily reliant on solid movement and rotation to create chances in the final third. So, while Chelsea’s defense soared, the offense stagnated.
Tuchel won’t mind given a 1-0 win is as good as a 4-2 win, but fans have wondered about what next season’s squad will look like. Three or four at the back next season at Chelsea will be dependent on the transfer window at that remains an open ended question. Or, at least it appears that way.
Most of the calls for four at the back point towards parts of Tuchel’s history. At Dortmund, he mostly ran with a 4-2-3-1 formation. At PSG, he was far more fluid but often times used 4-2-2-2 and 4-3-3. But, it should be noted that during his time at PSG in particular, Tuchel began to use three at the back on paper and in practice.
Marquinhos was a big driver of this. Equally capable of playing in midfield and as a centerback, the Brazilian blurred the line between back four and back three for Tuchel. And that is mostly the point. Tuchel wants his formations to be highly fluid and able to adapt to the opponent. Take the 3-5-2 used against Fulham, for example. With Mason Mount in the midfield trio on paper, what happens when he bursts forward and stays high when possession is lost? The 3-4-2-1 Chelsea has been using.
That fluidity is more in line with what Tuchel is looking for than three or four at the back. Cesar Azpilicueta and more recently Antonio Rudiger have often gotten forward into midfield to make the attacking shape more of a 2-3-5, but what Tuchel really needs is a player like Marquinhos that can allow the formation to swap completely and with fluidity. The same notion applies to the front three who should all be capable of swapping around with one another as well as changing shape.
Given how specialized the role is, it will be very hard for Tuchel to find that type of player in the market. He may find or be given players that allows him to start in 3-4-2-1 or 4-3-3 to partially mimic that fluidity but it will be hard to fully replicate without the right players.
For the moment, however, fans should not be too caught up on whether Chelsea plays three or four at the back next season. The answer is likely both will be used in some fashion, often within the same game. But to truly achieve what Tuchel was able to do at PSG, he will need one centerback or midfielder he can build the shape around and trigger changes as needed.