Ulster skipper Johann Muller could reportedly miss the remainder of the season with a bicep injury.
The South African suffered the blow in Saturday's Heineken Cup quarter-final defeat to Saracens, but it had been suggested that he could return in the next couple of weeks.
However, according to BBC Sport, the injury is more serious than first feared, with the 33-year-old expected to miss the remainder of the campaign.
Muller, who made 24 appearances for his country, has been with Ulster since 2010.
