Benjamin Mendy will be out of action for up to 12 weeks after having surgery on a knee injury, Manchester City manager Pep Guardiola said on Friday.
The France defender suffered the problem after City's 3-1 victory over neighbours Manchester United on November 11 and travelled to Barcelona last week for an operation.
Mendy has not suffered a repeat of the cruciate ligament damage in his right knee that forced him to miss much of last season and threatened his participation at the World Cup with France.
This time, the left-back has suffered an injury to his meniscus in his left knee, although Guardiola says he does not expect the full-back to play again before late February.
"It's 10 to 12 weeks," said Guardiola, who also confirmed that Bernardo Silva would not be fit to play in Saturday's Premier League match at West Ham.
The playmaker picked up a knock on international duty with Portugal. He may also miss City's Champions League clash at Lyon next week.
"He (Silva) cannot play this weekend. It's not too big but I don't know if, next Tuesday, he's ready," said Guardiola.
Saturday's fixture at the London Stadium will see league leaders City face their former manager Manuel Pellegrini, who won the league for City in 2014 and made way for Guardiola two years later.
Both managers know each other well from their La Liga days, as Pellegrini managed Villarreal, Real Madrid and Malaga during Guardiola's four years in charge at Barcelona.
Guardiola said: "His career speaks for itself in terms of quality. When you see the teams of Manuel Pellegrini, even you are a blind guy you recognise his style.
"His start was incredible in Villarreal and put this team at another level. It was a small, small city and the way they play and the way they create their own style was impressive. "After he went to Madrid and make a very good league (campaign) with 96 points but at Barcelona we did 99.
"Here he won the league and helped this club be where we are right now. And he did Malaga as well and he is going to do well at West Ham." Guardiola has hinted at the possibility that he could stay at City beyond the end of his contract in 2021, while playing down the idea that he may eventually move into international management.
"I said many times that I extended the contract and I don't deny too if it is going well, that I could stay more years here," he said.
"Everybody has dreams and when I was a little boy I had dreams and sometimes they are accomplished and sometimes not.
"I said maybe in the future I would like (international management). Maybe I will change my mind later but I am fully convinced in my mind here."
