Chelsea manager Andre Villas-Boas has admitted he is monitoring the situation of Gary Cahill.
The Stamford Bridge boss is thought to be interested in signing Cahill as a replacement for Blues outcast Alex.
Cahill is coming to the end of his Bolton contract and will be free to talk to prospective teams in January.
“We are aware of Gary's contractual situation. He's an interesting player for the club,” said Villas-Boas.
A fee of £7million has been mooted as the sufficient amount to convince Bolton to cash-in on their prized defensive asset.
Wanderers boss Owen Coyle has said he would like to keep the England international but the club are unlikely to allow him to leave on a free transfer.
Brazil international Alex is expected to move in January are being told he is no longer in Villas-Boas’ plans at Stamford Bridge.
This would leave the Blues short in the central defensive area, which is why they are being credited with an interest in Cahill.
“You know that we have taken a decision this season regarding the central defenders, regarding Alex,” added the Chelsea chief.
“We haven't decided yet what we are going to do with the Alex situation. We have to make the wisest decision, be it Alex, be it Cahill.”