Manchester City expect Aymeric Laporte to be out for up to six months, manager Pep Guardiola has revealed.
The Premier League champions confirmed last week Laporte had undergone surgery to repair cartilage and meniscus damage in his right knee.
No timeframe was put on the Frenchman's rehabilitation at that point but Guardiola has now indicated it could be well into the new year.
Asked how long the 25-year-old will be out, the City boss said: "Long - five or six months. January or February maybe, next year."
The injury to Laporte has exposed City's lack of cover in the central defensive department following the departure of former captain Vincent Kompany at the end of last season.
The news is at least offset by the return to fitness of England international John Stones after a thigh injury.
"He's good, he trained good," said Guardiola at a press conference, indicating Stones will be back in contention for the champions' trip to Norwich on Saturday.
City will travel to Carrow Road with forward Raheem Sterling in blistering form. The forward continued his great start to the season with two fine performances for England during the recent international break.
He has now scored eight goals in seven games for club and country and has even drawn comparisons with Lionel Messi and Cristiano Ronaldo.
Guardiola hopes he pays no attention to such hype.
He said: "I'm so happy for him, for the way he's playing here and with national team, but hopefully he won't read too much. He cannot listen to these kind of things - that would be good for him, because nobody can compare with Cristiano or Messi.
"I'm so happy with what he's done since we've been together, not just right now. Everything has happened to him has been good because he has an incredible work ethic and is an incredibly nice guy. I'm delighted for him."
Guardiola also delivered a positive updates on the fitness of Leroy Sane and Benjamin Mendy.
Sane is sidelined with a serious knee injury and there were fears he could miss most of the season but Guardiola expects him back well before the end of the campaign.
He said: "He did the injury in August, so December or January, maybe February. That should be perfect.
"I'm told the surgery was good. He came back two days ago and he is making his rehabilitation with us. Hopefully he can come back well and soon."
Mendy's two years at City have been ravaged by injury but he is making good progress in his recovery from his latest knee problem.
Guardiola said: "He's good and he's training now. I'm delighted because that's two weeks.
"Everything is going well, the knee is reacting well. Hopefully in the next games he can be part of it."