Zlatko Junuzovic will not return for SV Werder Bremen until 2016 after suffering a shoulder injury in Sunday's draw in Stuttgart.
A decision will be made on Tuesday whether or not the 28-year-old requires surgery.
Skripnik: 'We have to accept it'
"It's a blow for us, but that's football," Bremen coach Viktor Skripnik, whose side are just , said. "We have to accept it when a key player is sidelined. I hope he'll come back even stronger."
Junuzovic, who has featured in all but one of Bremen's 15 league games to date, providing two goals and a brace of assists, will miss next weekend's home encounter with 1. FC Köln, as well as next week's DFB Cup trip to Mönchengladbach and the Matchday 17 game at Eintracht Frankfurt.