Chelsea have reportedly had a bid for goalkeeper Craig Gordon rejected by Celtic.
The Premier League leaders are understood to be in the market for a back-up goalkeeper this month amid speculation that Asmir Begovic could leave the club.
Gordon has previous experience in the Premier League with Sunderland, but is currently the first-choice keeper for runaway Scottish Premiership leaders Celtic and could be unwilling to swap regular first-team football for a reserve role behind Thibaut Courtois.
Celtic are also unwilling to sell the 34-year-old, who has kept 11 clean sheets in 18 league appearances for Brendan Rodgers's side this season.
Speaking about the speculation over Gordon's future, Rodgers told reporters: "I am not surprised. His contract is up at the end of the season but there is an option for the club.
"It is not something we would consider really. It is a difficult decision for a player, especially if you are getting financial rewards at the end of it. But he knows Celtic is a huge club and he is very much part of what we are trying to build here."
Chelsea have also been linked with Diego Lopez, Fernando Muslera and Tim Krul in their search for a new number two.
