Bayern Munich have confirmed that striker Mario Gomez needs an ankle operation after being stretchered off in Saturday's match against Werder Bremen.
The 27-year-old left the field minutes after half-time and the club admitted that he will require surgery on the injured ankle.
Bayern sporting director Matthias Sammer said: "He is not good. He needs surgery. Then we'll see how long he's out for."
Munich lost the Liga Total! Cup semi-final on penalties to Werder Bremen after a 2-2 draw in normal time.
The German giants have a number of injury problems ahead of the start of the Bundesliga, with Rafinha, David Alaba and Diego Contento all facing a prolonged spell on the sidelines.