Maurizio Sarri says Chelsea must find a replacement for Cesc Fabregas should the midfielder move on in the January window.
Fabregas is expected to make the move to Monaco to join up with former Arsenal team-mate Thierry Henry, though the clubs are currently at odds over the fee.
The Blues are lining up a move for Italy international Nicolo Barella, while Zenit St. Petersburg star Leandro Paredes is also of interest.
And Sarri believes Chelsea will be "in trouble" if they fail to get someone in the door to fill the void left by Fabregas.
"If Cesc will go, of course we need a replacement. Now, with the midfielders we are in trouble, I think," he said.
"Without Cesc we have only five, so we are in trouble. We need a replacement."
Asked about speculation linking Chelsea with a £45million move for Barella, Sarri said: "I don't want to talk about players from other teams."
