Sean O'Brien ruled out of World Cup with hip injury
Sean O'Brien will miss the World Cup as he faces six months on the sidelines due to a hip injury which requires surgery.
O'Brien will leave Leinster for London Irish at the end of the season and at 32 years of age, that could mean the end if his international career due to the IRFU's strategy of only picking Irish-based players.
"Unfortunately (Leo) Cullen has confirmed that back row Seán O'Brien - who lifted the PRO14 trophy yesterday in Celtic Park on behalf of the 57 Leinster players that competed over the 23 game domestic season - will undergo surgery in the next few weeks for a hip injury and as a result will be ruled out of action for up to six months," read a statement.
"As a result he has been ruled out of the Rugby World Cup in Japan."
O'Brien sat out Leinster's Pro14 victory against Glasgow Warriors in Celtic Park on Saturday but Johnny Sexton gave him the honour of lifting the trophy.
"Yeah, we knew early enough in the week that Seány was struggling a little bit," said Sexton.
"And we wanted to make sure his last contribution wasn't Saracens.
"His last memory now will be lifting the trophy, there's not too many people who have lifted the trophy by themselves in Leinster. It's guys like Leo and Isa (Nacewa), they're the only two. The rest of the time we always do it in twos.
"It was fitting for him, we're really going to miss him. I'm going to miss him.
"To be fair, he's one of the best players I've ever played with. As a forward, I'd say he's the best. No offence to Leo.
"Just, other forwards in the world didn't have his drive, as a leader and a player we're going to miss him.
"Obviously, we drive things from within and make sure the younger players coming through are driving it."
London Irish boss Declan Kidney expressed his disapointment.
"We are disappointed for Sean that he is not in a position to compete for a place in the Ireland Rugby World Cup squad," he said.
"We wish him a successful operation and a speedy recovery and look forward to welcoming him to London Irish for the next stage of his career."