Ulster prop Paddy McAllister will be sidelined for the majority of the season after picking up a significant knee injury in training last week.
The 23-year-old has torn his anterior cruciate ligament and lateral collateral ligament, which will require surgery and thus rule him out for a large part of the season.
He will be assessed by a knee specialist in the next few days which will give a better prognosis for a return to action.