England scrum-half Danny Care has been ruled out of the World Cup in New Zealand with a toe injury.
The Harlequins number nine, 24, injured his left big toe during the 19-9 defeat by Wales in Cardiff on Saturday.
Care will have surgery on Thursday and is expected to be out for at least six weeks. England's first World Cup match is against Argentina on 10 September.
Care tweeted: "Absolutely devastated about my injury but in the best hands for my op tomorrow."
He added: "Wish the lads all the best to hopefully win the world cup!!"
England manager Martin Johnson will name his final 30-man squad for the tournament on Monday.
Care has 32 England caps and started all of England's Six Nations matches in 2010, before losing his place to Leicester's Ben Youngs last summer.
But Care has come off the bench in every Test since and also started the first World Cup warm-up match against Wales at Twickenham.
His misfortune is all the more untimely given Youngs has yet to play since undergoing knee surgery in July, although Johnson is confident he will be fit to face Ireland in Dublin in England's final warm-up match a week on Saturday, 27 August.
"We are all hugely disappointed for Danny who has worked extremely hard and has been an important part of the squad throughout our Rugby World Cup preparations," said Johnson.
"He featured in both warm-up fixtures and was on course for selection so this injury is really disappointing for him personally and for us as a squad. Nobody wants to see a player ruled out at this stage through injury and we all wish Danny a speedy recovery."
Former England centre Jeremy Guscott believes Care could have edged out his rival for a starting place in the team's World Cup opener against Argentina in Dunedin on 10 September.
"In the two warm-up games, I had been very impressed with Danny Care. I think he has been playing the best rugby he has yet for England," he said.
"He has been playing with authority and not trying to take on too much, which he has been guilty of in the past.
"If Care had still been there for that first match, I think it would have been a coin flip between them."
Saracens' Richard Wigglesworth, who started in the 19-9 defeat by Wales on Saturday, and Wasps' Joe Simpson could now both travel to New Zealand if Johnson opts to take three scrum-halves.
"They definitely have to take three now," England World Cup-winning scrum-half Matt Dawson told BBC 5 live. "It is a big blow for the England side because they are now low in the scrum-half department.
"I think Ben Youngs will be the starter but Joe Simpson could be one of those players who comes from nowhere, gets a little break and he could be a little star. He is a fantastic player, with blistering pace."