Chelsea boss Maurizio Sarri concedes Alvaro Morata could be on his way out this month.
The striker is a target for Atletico Madrid, though any move hinges on Chelsea signing AC Milan striker Gonzalo Higuain.
Ahead of Saturday's derby with Arsenal, Sarri stated: "I don't know if he will play, but he is training with us.
"That's normal. For him it's a very difficult moment, but it's normal for a player in January to be involved with the market. He is available, but like in the last match I can choose something difficult."