Mourinho ChelseaChelsea’s Belgian goalkeeper will be sidelined for “quite a long time” after sustaining a in the last training session, coach confirmed on Friday.

was injured in a training session with the goalkeepers,” the coach said in a press conference.

“I cannot tell you much but I can tell you he needs surgery on his right knee and as a consequence he will be out for quite a long time,” Mourinho explained.

“I cannot be more specific about the injury and about the time he will be out, but I know he will be out for some time,” the Portuguese coach added.

The injury of Courtois, former goalkeeper of Atletico Madrid, is another blow at the beginning of the season for the English champions, who are ranked in 13th place with an eight-point margin behind the leaders Manchester City.