PRO12: Leinster and Ireland flanker Sean O'Brien out for up to six months with shoulder injury

Leinster and Ireland flanker Sean O'Brien has been ruled out for up to six months with a shoulder injury.

The 27-year-old has been sidelined with an ankle injury since Leinster’s opening game of the season, but the recurrence of a shoulder injury resulted in O’Brien seeing a specialist last week.

Leinster coach Matt O’Connor confirmed that O’Brien will undergo reconstructive surgery in London on Friday.

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O’Brien dislocated his left shoulder against Ulster last December and had an operation the following month, ruling him out of Ireland’s successful Six Nations campaign.

The Carlow native returned in May to help Leinster retain their PRO12 title and he captained the province against Glasgow at the start of September, only to pick up an ankle problem.

Leinster medics were relieved to deliver the news the ankle issue was not as serious as first expected, but later discovered O'Brien was still suffering after-effects from his initial shoulder surgery.

"There was a little bit of a complication with the previous surgery due to the infection," said O'Connor.

"So they're going to have to redo that reconstruction, which is a five to six month time frame. It's a nightmare. He's incredibly frustrated."

O’Brien will miss Ireland’s autumn internationals against South Africa, Georgia and Australia, and is also a major doubt for next year’s Six Nations.