Senegal international striker Mame Biram Diouf will miss the rest of the season following shoulder surgery.
Diouf was injured while playing for Hannover against Bayer Leverkusen last week and had an operation on Friday.
It means the 26-year-old may have played his last game for the German club having declined to sign an extension to his contract which expires at the end of the current campaign.
Diouf has hit 30 goals in 68 games for Hannover since signing in January 2012.
He was linked with a move to Cardiff City in January this year.
Had he joined the English Premier League side he would have been reunited with boss Ole Gunnar Solskjaer, who he played with in Manchester United's reserves.