Tom Smith has been ruled out for up to eight weeks after picking up hip and knee injuries during the recent Magners League win over Connacht.
The 24-year old back rower was forced off early on in the 19-17 win on the 21st February, and scans have shown the extent of the damage.
Ospreys Physio Chris Towers confirmed:
"Tom has torn muscles in his hip, as well as damaging knee ligaments. He is improving as well as we could hope for at the moment, but we are looking at a recovery period of around six to eight weeks from the day of the game, which means that we are looking at a mid-April return to playing."