Celtic midfielder Beram Kayal will be out for the remainder of the Scottish Premier League season.
The Israel international sustained ankle ligament damage in the Old Firm win over Rangers on December 28 and after undergoing surgery will miss the rest of the campaign.
"Beram Kayal underwent surgery last night on his injured ankle and the club can confirm that, unfortunately, our worst fears have been realised and Beram will be out of action for at least four months," he told the club's official website.
Hoops boss Neil Lennon was left to rue the injury to a player who had become key over the first half of the campaign.
"He will definitely be a big loss for us, but more importantly we are disappointed for him to be missing such a large part of the season at a time when he was playing so well.
"Clearly his health and fitness is now our priority and we will be making sure he gets our total support during the coming period.""This is very sad news for Beram," said Lennon. "He has been brilliant for us and instrumental in our performances during the season.