Ulster’s Rob Herring and Rodney Ah You have been ruled out for six weeks as they sweat on the fitness of Ruan Pienaar.
Pienaar sustained a right knee injury in last week’s game against Leinster and will see a specialist this week.
He will be unavailable for the match with the Scarlets in the Pro12 on Friday.
Herring and Ah You sustained knee ligament injuries as Ulster’s injury list mounts. Craig Gilroy and
Roger Wilson will also miss the trip to Wales due to ankle and knee injuries respectively.
Wiehahn Herbst sustained a calf muscle tear in training and it is estimated that he will be absent for four to six weeks.
Kyle McCall has had surgery to repair a torn right hamstring sustained in the match with Clermont two weeks ago and the recovery period for this injury is likely to be four to five months.
Also unavailable for selection are Marcell Coetzee (knee), Peter Nelson (foot), Ricky Lutton (toe), Alan O'Connor (concussion), Stuart Olding (calf), Jared Payne (kidney) and Matthew Rea (shoulder) in a remarkable list of absentees for the province.
Ross Kane, Robbie Diack, John Donnan and Aaron Cairns have all recovered from recent injuries and are available for selection.
