Ospreys second row Rynier Bernardo has been ruled out for the rest of the season with a knee injury.
Bernardo, 23, suffered the injury during Ospreys' LV= Cup defeat to Gloucester in January.
The South African lock will undergo surgery later this week after scans confirmed a dislocated kneecap.
"The surgery means that he will miss the rest of the season," said Ospreys medical performance manager Chris Towers.
"Post op, we will be in a better position to confirm the likely extent of his lay-off, once we have seen the full extent of his injury."
Ospreys are already without locks Lloyd Peers and De Kock Steenkamp due to injuries while Alun Wyn Jones is on international duty with Wales.
Bernardo joined Ospreys on on a three-year deal during the summer of 2014 and has made 20 appearances in all competitions for the regions this season.