Ireland flanker David Wallace has been ruled out of the World Cup after sustaining a knee injury in today's 20-9 defeat by England at Aviva Stadium.
Wallace was driven from the pitch by a medical cart in the 21st minute after twisting his right knee while being tackled by Manu Tuilagi.
"David took a very bad bang on the knee and while we don't know the exact prognosis, he has unfortunately been ruled out of the World Cup," said Ireland coach Declan Kidney.
Kidney, who will name Wallace's replacement tomorrow, admitted the Lions openside's withdrawal was "heartbreaking" for Ireland and the player.
"David took the news like the man he is. There's a word I'm not supposed to say in public, but it happens," he said.
"You have to deal with these things. He's 35 and I've never seen a man as physically fit as he is right now. Never.
"It's heartbreaking for him and his family. It's extremely disappointing for us and will be good news for someone else. That's the cut-throat nature of sport."
A highly attritional match saw Ireland finish with a number of injury concerns, although apart from Wallace all are expected to be available to face the USA on 11 September.
Cian Healy (eye), Jerry Flannery (shin), Stephen Ferris (hand) and Jamie Heaslip (concussion) left the field early, but Kidney insists none have been ruled out of the World Cup opener.
Kidney eased concerns over Heaslip's condition.
"Jamie had to come off, but has come around fine and is talking away to the lads," he said.
"Hopefully with a bit of a rest he'll be OK."
Tries from Manu Tuilagi and Delon Armitage underpinned England's victory as Ireland slumped to a clean sweep of defeats in their World Cup warm-up games.
Kidney insisted he had no regrets over agreeing such a strenuous build up to the tournament.
"All of the lads have had around two games and they needed those two games," he said.
"If you go to the World Cup you want to compete at the highest level.
"We wanted to challenge ourselves against England and France to know exactly where we are, and we know now.
"We've lost four in the series, which is extremely disappointing. That's not what we aimed for.
"No excuses to camouflage results, we're here to get results. We'll keep working and will get better."
