Ireland appear set to be without Iain Henderson for the start of their Six Nations title defence after Ulster confirmed the lock will be out for "several weeks" with a finger injury.
Second-rower Henderson was hurt during the 14-13 European Champions Cup win over Leicester Tigers at the weekend having only just returned to action following thumb surgery.
Ulster confirmed in a statement that the latest injury is not related to the thumb that was operated on in December, though the setback suffered by the forward is a blow for Ireland ahead of this year's Six Nations.
Joe Schmidt's squad open their campaign against England in Dublin on February 2 before travelling to Edinburgh to face Scotland the following weekend.
The defending champions were already certain to be without versatile forward Tadhg Beirne for their first two fixtures due to a knee injury, with Quinn Roux drafted into the squad as a replacement.