Worcester Warriors scrum-half Francois Hougaard is set to miss up to three months due to a shoulder injury.
Hougaard, 28, was away with South Africa and, on his return, the Warriors were dealt a blow.
The Warriors said Hougaard needed a biceps tenodesis and rotator cuff repair, ruling him out for 10-12 weeks.
"We are extremely disappointed that Francois returned to the club with an undiagnosed injury," Warriors high performance director Nick Johnston said.
"As a club player welfare is our priority and we will be using our every resource to ensure that Francois has access to the right surgeon and that he receives the highest level of support during his rehabilitation."
The Warriors are next in action against Brive in the European Challenge Cup on Saturday before visiting Harlequins in the Premiership a week later.