Scotland centre Mark Bennett has undergone ACL reconstruction at BMI Ross Hall Hospital in Glasgow and could miss up to 12 months of rugby.
The Warriors centre, who will join Edinburgh next season, sustained the injury while playing for his country against England last month.
He is expected to be out of action for 9-12 months.
Meanwhile, back-row Josh Strauss, who sustained an injury to his kidney playing for Scotland against France in February, has been reviewed by his consultant and his injury is healing well. He'll require a further six weeks of non-contact work before he can return to full training.
"We're disappointed that Mark's time at the club has come to an end in this way, and it also looks like Josh may not play for us again as he continues his graduated return to training," head coach Gregor Townsend told Glasgow's website.
"We wish both players all the best with their rehab and look forward to having them as part of our wider group for the remainder of the season."