RB Leipzig goalkeeper and captain Peter Gulacsi is set to miss a "lengthy period of time", after being diagnosed with an ACL tear in his right knee, the club tweeted.
Gulasci, 32, was injured early in his team's 3-1 home win over Celtic in the Champions League on Wednesday night, attempting to clear a back pass from Timo Werner.
The Hungarian international was stretchered from the field and replaced by debutant Janis Blaswich.
Manager Marco Rose said after his side's victory "it really hurts with Pete" and promised the club would support Gulacsi for the duration of his recovery.
"He's our captain and has been an absolute fixture for Leipzig for years.
"It didn't look good," Rose said about the injury in the post-match press conference.
"We ended up winning the game for Pete as well. We are wishing him a speedy return."
Gulacsi, who was on the books at Liverpool for five years without starting a game, joined Leipzig in 2015 and captained the side as they won their first ever silverware, the 2021-22 German Cup.
Gulacsi's teammate Dani Olmo tweeted on Wednesday evening "I'm sure you will overcome this situation and come back stronger than ever. Get well soon, captain! We are all with you."
Teammate Lukas Klostermann, who ruptured his ACL in 2016, tweeted late on Wednesday "It will be tough, but you will master it and come back stronger."
The club announced the initial diagnosis on Wednesday evening, with a final diagnosis to be made public on Thursday afternoon.