Glasgow Warriors scrum-half Chris Cusiter has been ruled out until around mid-December with a dislocated shoulder.
Cusiter sustained the injury during last Friday's 28-10 win over Ospreys, and has since been assessed by a shoulder specialist.
The positive news is that Cusiter's injury does not require surgery.
Glasgow Warriors head coach Gregor Townsend said the 30-year-old's injury was a setback for the club.
"Everyone at Glasgow Warriors is disappointed that a quality player like Chris Cusiter is likely to be out of action until around the middle of December," he told the club's official website.
"It's encouraging, though, that he doesn't need surgery, and we know he's in the best possible hands with our medical team.
"Chris is a tough competitor, and he'll be working hard to return to fitness and make a significant contribution to our campaign.
"We wish him well with his rehab, and look forward to welcoming Niko Matawalu to the club to supplement our options in the scrum-half position."
Cusiter's injury is also a blow for Scotland head coach Andy Robinson.
"It's disappointing for Chris because he has made such a good start to the season. I wish him a speedy recovery."