Manchester City have revealed that defender Benjamin Mendy has undergone knee surgery.
Mendy missed the majority of the last campaign with a serious knee injury, and although this issue is with his opposite knee, the Frenchman faces an extended period on the sidelines.
A club statement read: "Manchester City can confirm that Benjamin Mendy has undergone surgery on his left knee tonight.
"The Frenchman, who played the full 90 minutes in the weekend's 3-1 win over rivals Manchester United, travelled to join up with his national team before withdrawing from the squad.
"The 24-year-old defender attended Dr. Cugat's clinic in Barcelona where scans revealed that surgery was required. That surgery was conducted on Wednesday evening and everyone at Manchester City wishes Benjamin a speedy recovery."
Mendy had enjoyed an excellent season with the Premier League champions, with five assists coming from his 10 starts in the top flight and Champions League.
A report in The Mirror has suggested that City have been managing Mendy's knee problem during the opening three months of the season.