Sean O'Brien is a major doubt for the start of Ireland's Six Nations campaign after undergoing a 'small procedure' to deal with a hip problem.
The Ireland flanker has been sidelined since Leinster's Champions Cup victory over Exeter Chiefs in December, but hoped that he would return for this weekend's clash against Glasgow have been dashed.
Leinster boss Leo Cullen said: "Sean O'Brien saw a specialist this week for the tightness in his hip as it hasn't responded to treatment as we would have liked.
"As a result he had a small procedure and the target is to have O'Brien back available during the 6 Nations window."
Ireland kick-off their Six Nations campaign with a trip to Paris to take on France on Feb. 3.