Alex Dunbar faces a race against time to be fit for Scotland's November internationals clashes after being ruled out for the next six weeks.
The 27-year-old centre injured his right knee during Glasgow's victory over Cardiff Blues earlier this month.
That forced him to undergo surgery but Warriors management say the procedure carried out at the BMI Ross Hall Hospital in Glasgow was a success.
However, Dunbar faces a six-week recovery period and that will leave him with little time to prove his sharpness ahead of Scotland's November Tests against Samoa, Australia and New Zealand.
Samoa are first to visit Murrayfield on November 11 with the Wallabies and All Blacks then taking on Gregor Townsend's side on the following two Saturdays.
Glasgow have also confirmed Dunbar's Scotland colleague Fraser Brown is back in full training ahead of Friday's game against Benetton Treviso at Scotstoun after he shook off an ankle injury.
Fellow internationals Jonny Gray and Stuart Hogg are making good progress in recovering from their wrist and shoulder injuries, as is former Scotland under-20s fly-half Adam Hastings, who has been struggling with thigh issues.
Loosehead prop Oli Kebble has been told he does not require surgery on a foot injury sustained on his home debut against the Ospreys earlier this month.
However, Kebble, who arrived from South African side the Stormers this summer, is expected to be out of action for 10 to 12 weeks.