Unusually for Chelsea, their main problems this season have come in the form of defensive frailties.
So Alex's tiff with Andre Villas-Boas won't have helped matters.
The Brazilian centre-back has been part of the squad for several seasons now, and having been transfer-listed, there are going to be some big shoes to fill in the Chelsea back four.
Gary Cahill looks set to move to Stamford Bridge, but there could also be other players who could be brought in to fill this hole.
Here is a list of some of the possible contenders.