Borussia Dortmund midfielder Marco Reus faces several months out of action after suffering a partial cruciate ligament tear during Saturday's DFB Pokal final win over Eintracht Frankfurt.
Germany international Reus was substituted at half-time in the 2-1 win at Berlin's Olympiastadion and Dortmund confirmed the extent of his injury on Monday.
A statement on the club's official website said: "Further examinations will be conducted over the next few days to determine what course of treatment is required.
"With this in mind, Borussia Dortmund will not at this stage make any precise estimations as to the possible length of the player's absence.
"BVB wish their DFB Pokal hero the speediest possible recovery."
- POKALSIEGER 2017 �� (@BVB) May 29, 2017
Earlier reports had suggested that Reus could face six months out, but the player told ARD during the postmatch celebrations: "You'll have to ask the doc. It doesn't matter today."
The Germany international had already missed much of Dortmund's season through injury.
"Reus received a knock when running into the box," Thomas Tuchel added in his postmatch news conference.
The DFB Pokal win was Reus' first major trophy after losing the final three times previously, finishing as a Bundesliga runner-up on three occasions and losing a Champions League final in 2013.