Worcester have voiced their displeasure after claiming that South African Francois Hougaard returned from international duty with "an undiagnosed injury."
Hougaard, who has won 39 caps and was part of the Springboks' recent Rugby Championship campaign, is to undergo shoulder surgery.
But the extent of his injury only surfaced when he underwent checks by Worcester's medical department after reporting back for club duty.
Hougaard is arguably Worcester's most influential player, but he is now set to miss a long spell of domestic and European action and is unlikely to play again this year.
The 28-year-old is equally adept as a scrum-half or wing, and he has extended his stay with Worcester after initially joining them on a short-term deal last February.
In a statement, Worcester said: "T he Warriors medical department assessed Hougaard on his return to Sixways and diagnosed the player with a shoulder injury.
"Hougaard visited specialist consultants following the diagnosis and was given an MRI scan to allow the club to fully understand the extent of the injury.
"The scan confirmed that Hougaard will need a Biceps Tenodesis and rotator cuff repair and will be ruled out of action for 10 to 12 weeks."
Worcester's hi gh performance director Nick Johnston added: "We are extremely disappointed that Francois returned to the club with an undiagnosed injury.
"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."