Chelsea manager Jose Mourinho believes that midfielder Kevin de Bruyne has struggled to adapt to life at Stamford Bridge.
De Bruyne has rarely featured for Chelsea since returning to the club from a loan spell with Werder Bremen, but Mourinho has insisted that the Belgium international won't be allowed to leave the club for a small fee.
The 50-year-old told reporters: "This is a period for agents to be famous. We know that Kevin didn't adapt to the difficult life that a Chelsea player has, which is to pay a big price to play.
"You have to give a lot, to work a lot, and to accept competitiveness. This is the first time that he came to a big club with big competition. He is a fantastic player with fantastic potential.
"If people think that they can get our good players on sale, then the sales finished in London yesterday."
Mourinho also revealed that the club had received contact from "a couple" of clubs regarding De Bruyne's availability.