Bayern Munich could be without defensive midfielder Luiz Gustavo for the rest of 2012 after the Brazilian underwent surgery on his groin rather than flying to Valencia with his team mates.
With only five weeks to go before the Bundesliga goes on its winter break, the chances of the 25-year-old playing again this year appear slim.
"It's a painful loss," said Bayern coach Jupp Heynckes in Valencia. "I don't know how long he is going to be out for.
"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."
Gustavo, who joined Bayern from league rivals Hoffenheim last year, has been a regular for the Bavarians, even keeping the league's record signing Javi Martinez out on occasions.
His loss leaves Heynckes shorter on options for a busy schedule of matches between now and Christmas.