Glasgow and Scotland centre Richie Vernon will miss most of the remainder of the season after shoulder surgery.
The 28-year-old, who started one match during last year's World Cup, was injured in the Warriors' defeat by Northampton in November.
"He failed to progress as expected, so an operation was required, which will keep him out for most of the season," said head coach Gregor Townsend.
Vernon was left out of Scotland's Six Nations squad.
Club-mate and fellow centre Peter Horne was one of several injured players included in Vern Cotter's party, with Glasgow reporting he is making "good progress" from a foot problem and "working hard to get back soon."
The Pro12 champions also say flanker Rob Harley has joined in with training in recent days as he recovers from a thumb injury.