Werder Bremen defender Sebastian Prodl will not play again this season after undergoing surgery on a torn buttock muscle.
Prodl, 23, picked up the injury in training last Thursday and has already had an operation.
Surgeon Dr Martin Leonhardt said the injury was "unique" and had occurred in an "extremely extraordinary position". Prodl now faces several months on the sidelines until the muscle tissue recovers.
"I have just got to accept the facts and learn to deal with it," Prodl said in a statement. "Unfortunately, there is no experience with this extremely rare injury, but I will do all I can to get back to playing for Bremen and the national team as quickly as possible."
Prodl has spent the whole weekend in hospital, but should be discharged on Monday.
He added: "It really hurts me not to be able to help Bremen during the final stages of the season, but I will be at every game with all of my heart and will be keeping my fingers crossed for my colleagues."
Prodl has played in 35 games for Bremen this season, missing just one match due to suspension.