Joe Schmidt has revealed that Sean O’Brien is unlikely to play again until the end of the current season at the earliest.
The 26-year-old dislocated his shoulder in Leinster’s RaboDirect Pro12 victory over Ulster at the end of December.
Speaking to Ryan Tubridy on last night’s Late Late Show, Ireland head coach Schmidt said: “Sean had an operation last Friday and he’s likely to be out for four months, maybe beyond that.”
A four-month absence will mean O’Brien will miss the entire RBS Six Nations campaign.
He is also unlikely to be involved for Leinster until the very end of the season.
The RaboDirect Pro12 is scheduled to conclude on 31 May, while the Heineken Cup due to finish a week before on Friday 23 May.
O'Brien has been the subject of significant transfer speculation for the past month and it has also been reported that the Leinster and Ireland flanker is in France this weekend with Toulon seeking his signature next season.
Live radio coverage of Castres v Leinster on Heineken Cup Special from 12.30 on Sunday 12 January on RTÉ 2fm and RTÉ.ie (Worldwide).