Ospreys back Gareth Owen is likely to miss the whole of next season after injuring his knee in training.
The 22-year old Maesteg-born back, who has 50 appearances for the Ospreys, underwent surgery on Thursday.
"It was a bit of a freak accident resulting in him twisting his knee," said Ospreys head physio Chris Towers.
"As a result of this he will, in all likelihood, be out of action for the whole of the 2011/12 season."
Owen will undergo a second operation to repair the damage and to reconstruct the cruciate ligament.
Towers added: "At this stage we are unable to say anything more, but will update on his progress as and when we can."