Squad bottlenecks can be a good thing if the manager can rotate everyone enough. Chelsea has a big one happening at centerback thanks mostly to David Luiz.
An ideal squad is at least two deep with players natural to a position. For a spot like centerback where two play at a time, that means four players. But not all four of those players need to, or perhaps should, be of the same skill level.
Ideally, centerbacks are rotated little so partnerships can be formed. There are the main two and one that rotates in and out. Then there is a younger fourth choice that knows he will get less minutes.
Chelsea does not quite have that dynamic this season because of David Luiz’s extension. With the Brazilian signing for two years, there were likely assurances that he would still be key in the first year of that contract. With Andreas Christensen and Antonio Rudiger sure to have spots themselves, that leaves just one spot for either Tomori or Zouma.
Many fans love the idea of keeping Zouma but will he get enough minutes to justify staying? Do not forget, Zouma opted to leave on loan under Antonio Conte because he did not want to be back up. As good as he is, he still would likely be a backup and it is unlikely that Luiz spends this season lower than third choice.
Meanwhile, Tomori is young and would understand not getting many minutes. Frank Lampard already knows him well and might opt to keep him knowing he is easier to deal with as a fourth choice.
That would mean either another loan for Zouma or a transfer. Everton are interested in the latter and the player is likely to avoid another loan. If the option is Zouma getting few minutes or getting a good transfer price while trusting Tomori, then Chelsea may just opt to move on from the Frenchman.
All of this could have and very much should have been avoided by letting Luiz’s contract expire. For all the leadership he brings to the locker room, it was not worth putting Zouma or Tomori’s fate into uncharted waters.
Of course this could all be something Lampard already has a plan for. He could have convinced Luiz to accept being fourth choice (as he should be). And he could be planning to rotate center backs far more often than he did at Derby County where he had no rotation options.
Some also think a back three might suit the squad but that merely shifts the bottle neck from center back to midfield or the front line. So while Lampard could do it, it does not really solve the situation.
Chelsea has a lot of center backs that should be playing. Lampard really only needs four natural ones and he has at least five as things stand. Someone will have to make way while the other four all need to be kept happy with the minutes they are getting.
Christensen and Rudiger are shoo-ins. Luiz likely is too for this season due to the nature of his contract. So between Zouma and Tomori, something will have to be settled over the next few preseason fixtures.