Chelsea manager Andre Villas-Boas has confirmed he will try and sign a new central defender in the January transfer window.
Chelsea's need for defensive reinforcements increased on Thursday night when Branislav Ivanovic picked up an injury against Tottenham and Jose Bosingwa was forced to switch from right-back to central defence to partner John Terry.
Alex seems set to leave Chelsea after handing in a transfer request, while David Luiz is also missing through injury.
Bolton defender Gary Cahill has been strongly linked with a move to Stamford Bridge, with Villas-Boas admitting he is an admirer of the England international.
Bolton could be forced to sell Cahill next month with the defender out of contract at the end of the season and they would prefer to get a fee for the player rather than risk losing him for nothing in the summer.
Villas-Boas could welcome back Luiz for the Boxing Day clash with Fulham, but the Portuguese tactician admits a new defender is his top transfer target in the January window.
"We could have David Luiz available to return on Boxing Day," said Villas-Boas. "But we are in the market for another centre-half and we have to respond quickly when the transfer window opens."