Ireland flanker Sean O'Brien is doubtful for Ireland's November Test series as he faces a four-month lay-off to recover from a hip operation.
O'Brien is scheduled to undergo corrective surgery this week.
The back row is also likely to miss the opening games of Leinster's Heineken Cup defence in October.
The former European player of the year took part in Ireland's recent 3-0 series loss to New Zealand, but his injury has curtailed his training.
"Sean is having some keyhole surgery on his hip to repair some cartilage damage within the next week or so, and the recovery period for this type of operation is 13 to 15 weeks," said Ireland manager Mick Kearney.
"It means it could be up to four months. Obviously it's going to make him doubtful for November.
"Like any operation there is some risk attached to it but the medics feel he will make a full recovery and that he will certainly be back towards the end of October, and he should be back playing Heineken Cup rounds three and four in December."
Kearney added that O'Brien's Leinster team-mate David Kearney had a similar procedure carried out as did Rhys Ruddock, both of whom are also facing lay-offs.
Ireland will play South Africa and Argentina in Dublin in November, while an Ireland XV will face Fiji.