Ulster full-back Ethan McIlroy sustained a “significant” knee injury in Saturday’s Investec Champions Cup defeat away to Leicester Tigers.
McIlroy, who was making his return from injury, was forced off after 22 minutes of the game at Welford Road after pulling up hurt when catching the ball.
Ulster said on Tuesday that the 24-year-old will visit a specialist to determine the extent of the injury.
Wing Zac Ward will follow return-to-play protocols after being forced off with a concussion midway through the second half.
In a boost to head coach Richie Murphy’s back-three options, Michael Lowry and Stewart Moore have returned to full training ahead of Ulster’s final Pool A match with Exeter Chiefs and will be assessed for selection.
First-choice hookers Rob Herring and Tom Stewart will also be monitored ahead of the game after returning to training from injury.
Progression in the Champions Cup is unlikely even if Ulster defeat Exeter on Friday; however, a draw or victory in Belfast would secure fourth in the pool and a place in the Challenge Cup.
Ulster have lost all three of their European matches so far this season, to Toulouse, Bordeaux and Leicester, while Exeter are also winless in the competition.
