Ulster are likely to be without John Cooney and Robert Baloucoune for Friday night's Rainbow Cup game against Munster at Thomond Park.
Scrum-half Cooney and wing Baloucoune sustained concussion in last Friday's defeat by Leicester Tigers in the Challenge Cup semi-final.
The pair are now following the Graduated Return to Play Protocols.
It is Ulster's second game in the Rainbow Cup after going down to Connacht in their opener.
Peter Sullivan's last-gasp try gave Connacht a 26-24 derby victory in a dramatic Kingspan Stadium encounter.
Ulster are already missing Jack McGrath (hip), Luke Marshall (knee), Cormac Izuchukwu (knee), Stewart Moore (hip),and David O'Connor (shoulder) for the trip to Limerick.