Glasgow winger DTH van der Merwe is likely to miss a "significant portion of the season" after being told he needs surgery on his injured shoulder.
Routine checks on the Canada international's fitness following his return from the World Cup highlighted an issue with his shoulder and further assessment from specialists has confirmed the 25-year-old needs an operation.
Warriors team doctor Gerry Haggerty said: "At this stage, it's very difficult to put an estimate on the likely recovery time, but clearly we will continue to monitor DTH closely."
Head coach Sean Lineen said: "It's obviously disappointing that a quality player like DTH requires surgery, and everyone at the club wishes him all the best for the operation and his subsequent rehabilitation."
Van der Merwe has not been included in the Warriors' initial 38-man squad for the Heineken Cup ahead of the tournament launch in London on Monday.