• Goalkeeper picked up knock on return to training with Chelsea • Asmir Begovic set to step up in place of Courtois

Thibaut Courtois has undergone surgery to his right knee and is expected to be out for up to three months.

The Belgian goalkeeper returned unscathed from international duty only to tear the meniscus in the knee during a training session with the club’s other goalkeepers on Wednesday. He had the operation in Barcelona on Thursday at the city’s Clinica Quirón.

Chelsea said in a statement on Friday that Courtois had “surgery on an avulsion of the posterior corner and medial part of the internal meniscus of his right knee. The successful surgery consisted of a reattachment of the meniscus by suturing”.

Mourinho described the setback as a “big blow” but he said that he would not complain about it. Asmir Begovic, the summer signing from Stoke City, will deputise with the 21-year-old, Jamal Blackman, now promoted to the substitutes’ bench.

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Blackman has made only one senior appearance so far in his career – for Middlesbrough, during a loan spell last season, in the Capital One Cup defeat at Liverpool. After a 2-2 draw, Middlesbrough lost 14-13 on penalties.

“It’s a big blow but you will not see me speaking again about Thibaut,” Mourinho said. “It’s not easy to have the best goalkeeper in the world injured. But it is easy to have one of the best goalkeepers in the world to play. Begovic is very, very good. I’m sad for Thibaut and sad for the team but we have a top goalkeeper and Begovic will be in goal.”

On Blackman, Mourinho said: “The third goalkeeper is always a complicated situation. You can be third goalkeeper and not sit on the bench once all season. Or you can be third goalkeeper and play a big match. In my first spell here, Hilário played against Barcelona when he was the third goalkeeper.

“Our decision was that the third goalkeeper would be a young English goalkeeper, behind two fantastic goalkeepers. We think that’s a good decision. We lose Courtois for a long, long time and now Jamal becomes the second.

“He was on loan at Middlesbrough and he did not play one single match in the Championship, just one cup match against Liverpool. He does not have experience but he has potential.”

Mourinho had a sarcastic comment for Fifa, after hearing that the governing body had made a statement about the on-going fallout from Mohamed Salah’s season-long loan move to Roma. Salah spent last season on loan at Fiorentina and the Italian club felt that they had an agreement with Chelsea to take him back. Salah, though, opted for Roma and Fiorentina have now lodged an official complaint with Fifa over breach of contract.

A Fifa spokesman said: “We can confirm having received a claim from the Italian club, Fiorentina, against the English club, Chelsea, and the player, Mohamed Salah, for breach of contract. The matter is still pending and being investigated.”

Chelsea did have an agreement with Fiorentina but it was dependent on Salah wanting to go back there. He did not and so, in Chelsea’s eyes, the agreement was null and void. Mourinho said: “I am happy that Fifa have time for other things in the middle of such great weather around them.”