Ibrahim Afellay has been ruled out of Schalke's Champions League last-16 clash with Galatasaray next month after suffering a torn thigh muscle.
The Dutch midfielder will be sidelined for "at least two months," according to a statement on the Gelsenkirchen club's website, after sustaining the injury at Schalke's winter training camp in Doha.
The 26-year-old has already flown back to Germany to begin rehabilitation, but a return is unlikely before March meaning he could miss both legs of the Champions League clash against Galatasaray as well as a host of Bundesliga matches.
Team-mate Christoph Moritz has also flown back to Gelsenkirchen after tearing knee ligaments, although his injury is not reported to be so bad and he could still be available for Schalke's first Bundesliga fixture of 2013, against Hannover on January 18.
The midfielder was three games into his comeback from a four-month lay-off with hamstring problem when he was stretchered off with a knee injury during the January 2 defeat by St Johnstone.
The 29-year-old said in several newspapers: "I'm absolutely devastated. I thought all my injury worries were behind me when I made my comeback against Celtic on Boxing Day.
"I was really raring to go in the second half of the season, but then this goes and happens and it's just floored me.
"It's been a nightmare season for me after firstly being out since August and now this latest setback.
"Any player will tell you when you're ruled out for the rest of the season there's nothing worse. It's so frustrating I won't be able to help the lads on the park.
"All going well I'll get the operation on my knee within the next few days and we'll just take things from there."