Bayern Munich coach Jupp Heynckes will have to do without Luiz Gustavo for the rest of 2012.
The defensive midfielder recently suffered a groin injury and he has now undergone surgery.
It is unknown how long Gustavo will be sidelined for, but Bayern fear he will not return before the winter break.
"It's a painful loss. I don't know how long he is going to be out for," Heynckes told reporters.
"He is an important player in my system and I hope to have him back as soon as possible. He's been having a good season."
The 25-year-old has made nine Bundesliga appearances so far this term, netting three goals in the process.