Ulster are sweating on the fitness of Marcell Coetzee for Friday's clash against Ospreys.
Coatzee picked up a thigh injury in last week's 19-13 win over Glasgow Warriors.
The South African is being assessed by Ulster's Medical Performance Team.
In a statement, Ulster said: "The Ulster Rugby Medical Performance Team has issued a squad update ahead of Friday’s Guinness PRO14 Round 13 fixture against Ospreys at Kingspan Stadium.
"Marcell Coetzee suffered a thigh muscle contusion in Ulster Rugby’s Guinness PRO14 Round 12 match against Glasgow Warriors. His availability for selection for the upcoming game against Ospreys will be assessed through the coming week.
"There are no other new injury concerns arising from Friday night’s game at Scotstoun Stadium."
