A thumb injury is expected to keep Iain Henderson sidelined for up to 12 weeks and the second row is in danger of missing the entire Six Nations campaign.
The Ulster lock, who impressed in a try-scoring performance against Scarlets art the weekend, has already undergone surgery and will definitely miss Ulster’s final two pool games in the Heineken Champions Cup.
The 26-year-old is now a major doubt for Ireland’s defence of the Six Nations.
A 12-week timeline would see the versatile lock return the second weekend in March, a week before the final round of games in the tournament when Ireland travel to Cardiff to take on Wales.
