Hannover 96 midfielder Lars Stindl has undergone successful surgery for a ligament injury in his right foot but a return date has not yet been set for the 24-year-old German, the Europa League competitors said on Tuesday.
Stindl was injured during the 2-2 draw at Spain's Levante in the Europa League last week and was taken off.
"Everything has gone well," the club said in a statement following the player's surgery in Switzerland. "But it is still unclear how long he will be out of action."
Hannover have qualified top of Europa League Group L for the next round of the competition.