Pep Guardiola has claimed that Manchester City full-back Benjamin Mendy could be out of action "for a long time" and has hinted at signing a replacement in January.
The summer signing jarred his right knee challenging Andros Townsend during City's 5-0 win over Crystal Palace at the Etihad Stadium on Saturday and was substituted inside half an hour.
City's medical team had hoped that Mendy had just suffered an impact injury, but following the club's Champions League 2-0 victory over Shakhtar Donetsk, Guardiola gave a pessimistic prognosis.
"After tomorrow he is travelling to Barcelona and we are going to see. But I get the impression he will be out for a long time, unfortunately," the Spaniard told BBC Sport.
"It is very frustrating, firstly for him first as a person - it is very sad for him. And, for the way we want to play, we will lose a lot. It is a major set-back.
"He is a unique player. We will see in January about a new signing. We have alternatives."
Mendy joined City from Ligue 1 champions Monaco this summer for a reported £52m.