Leinster flanker faces surgery
Sean O'Brien will miss Ireland's tour of South Africa and could also miss the start of Leinster's campaign next season.
The province have confirmed that O'Brien is now facing surgery on his troublesome hamstring injury, which is likely to rule him out for a considerable period.
Leinster head coach Leo Cullen has also issued an update on Cian Healy, who remains on the injury list with a number of worrying niggles.
The prop is unlikely to feature again this season and Cullen has confessed that they are still trying to establish the best course of action for his recovery.