Leroy Sane is facing a lengthy lay-off after suffering anterior cruciate ligament damage, Manchester City have announced.
The German winger, who limped off in the early stages of Sunday's Community Shield win over Liverpool at Wembley on Sunday, is to undergo surgery in the coming week.
The injury comes after a summer of speculation over the 23-year-old's future, with Bayern Munich having been heavily linked with the player.
Sane has been offered a new contract at the Etihad Stadium but has not yet signed. He has two years left on his present deal.
City have not put a timescale on the player's return but Ilkay Gundogan and Benjamin Mendy have both had seasons ruined by similar problems in recent years.
A statement from the club read: "Leroy will have surgery in the coming week.
"Manchester City will provide Leroy with all the support and guidance he needs, and everyone connected with the Club wishes him a quick and full recovery."