Scotland forward Johnnie Beattie is facing up to six months on the sidelines after being told he needs shoulder surgery.
The 24-year-old will undergo an operation in Edinburgh this week with Glasgow team-mate James Eddie also expected to go under the knife for a similar problem.
Beattie has been warned he could face half a year out of action but he is hopeful of making an early return.
Beattie, who won his 14th cap in Scotland's Test series triumph in Argentina last month, told www.glasgowwarriors.org: "It's probably too early to say definitively how long I'll be out.
"Prior to the operation, the surgeon is talking about a six-month window to get back but that's quite cautious and if I regain the strength at the same level as my right shoulder then it should be sooner."
Scotland A player Eddie will also be missing from Glasgow's back row for an extended spell after dislocating his left shoulder in training last week.
Warriors head coach Sean Lineen said: "We wish both Johnnie and James a speedy recovery and we're grateful for the expert medical attention they are receiving.
"Currently there are a number of bumps and bruises within the camp. Happily, however, our physiotherapists are confident that the vast majority of players on the treatment bench at the moment will be fit for our first Magners League game against Leinster in September."