Manchester City defender Benjamin Mendy is facing another spell on the sidelines after undergoing surgery on a left knee injury, the club have confirmed.
It is understood that the procedure relates to a meniscus injury, one that is not as serious as the right ACL injury that kept him out for most of last season.
No official timeframe has been put on his recovery.
A statement on the City website says: "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."
The defender played all 90 minutes of City's 3-1 derby victory over United on Sunday, but was forced to withdraw from the France squad the following day.
Mendy confirmed the injury on Instagram in trademark style, saying: "Other knee was jealous but the operation went well and its all good now."
City sources have told Goal that Mendy felt discomfort in his knee following Sunday’s Manchester derby, and subsequent examinations, by the French national team medical staff City doctors and Dr Cugat, confirmed the need for surgery.
Though he recovered from his ACL tear in time to make France's victorious World Cup squad this summer, Mendy's injury problems continued when he missed a month earlier this season with a foot injury.
The defender returned from that problem and has made 10 total appearances for City this season, but is now facing another spell on the sideline.
City return to action after the international break when they travel to West Ham on November 24.