Chelsea have announced that midfielder N'Golo Kante has undergone surgery on the back of his thigh and will not return until mid-February.
N'Golo Kante was on the verge of returning to the first team and was already training with the first team, but then, as Chelsea coach Graham Potter said, there was a relapse.
The relapse turned out to be so serious that it required surgery. Kante has already been operated on and now the Frenchman is starting a long course of rehabilitation.
"Together with the club's medical department, the midfielder visited a specialist to explore rehabilitation options and it was mutually agreed that Ngolo would undergo surgery to repair the damaged tissue.
The operation was a success and Ngolo is now expected to miss four months," the Blues said in a statement.