Tommy Bowe will miss the rest of Ulster’s European Cup group matches and is facing a lengthy lay-off after suffering a knee injury during Saturday's defeat to Northampton Saints at Ravenhill.
The 28-year-old international wing has sustained significant lateral ligament damage to his right knee and will undergo surgery in the next few days to repair the damage.
Bowe, a leading contender for the British and Irish Lions squad, was hurt when he landed awkwardly following an attempted tackle by Jamie Elliott in the closing stages of the game.
An Ulster statement read: "At this stage it is not possible to put a timescale on how long his recovery period will be.
"A further update on this will be issued following the surgery, when the full extent of the injury will be known."
Bowe has scored 23 tries in 51 European Cup appearances but will now face a race against time to be in contention for the 2013 Six Nations Championship.