Borussia Dortmund midfielder Mario Gotze has torn a muscle and faces a battle to be fit for the Champions League final against his future employers Bayern Munich, the club have confirmed.
"Mario Gotze tore a muscle in his thigh in the Champions League return leg at Real Madrid on Tuesday," a Dortmund statement said on Thursday.
"According to [club doctor] Dr Braun, returning to fitness for the Champions League final against Bayern Munich at Wembley is a realistic goal."
Germany international Gotze, 20, signed for Bayern in a €37 million deal in late April and moves to Munich in the summer.
Speaking prior to Dortmund's game in Madrid - which they lost 2-0 to go through 4-3 on aggregate - Germany international Mats Hummels told Sky that news of Gotze's departure had come as a shock.
"Mario is one of the best ten players in the world, maybe even higher than that," he said. "It was a shock. I did not sleep that night."
Hummels explained that he believed the Gotze transfer also illustrated the fact that Dortmund, despite recent success, still face a struggle to hold on to key players.
"You can either contribute your part to get your club there or you can switch to a club that is already there," he said.
"That is what it makes very difficult for all of us, because we will lose a player who knows exactly how we think, who has been part of this club from his youth - but who still prefers another German club. It is hard."