Second row Dan Tuohy is set to miss the remainder of Ireland’s Six Nations campaign and is also a doubt for Ulster’s Heineken Cup quarter-final against Saracens in Belfast on 5 April.
Tuohy suffered a fractured forearm after coming on as a replacement during Ireland’s convincing 26-3 win over Wales at the Aviva Stadium on Saturday.
He is expected to be ruled out of action for six to eight weeks.
Fellow Ulster lock Lewis Stevenson injured his neck against the Ospreys.
His injury will be assessed on Monday ahead of the Pro12 game with the Scarlets at Ravenhill on Friday night.
With Tuohy sidelined, Iain Henderson is likely to move up the pecking order with Ireland for the crucial clash with England at Twickenham on Saturday 22 February.