England hooker Steve Thompson will miss the World Cup starting in September after learning he requires surgery next week to try to repair his damaged neck.
Thompson was part of England's World Cup-winning side in 2003
The operation means the Northampton forward, who is already out of the Six Nations, will sit out the rest of this campaign and the start of next season.
Thompson's last game for Saints was against Biarritz on 21 January.
Northampton coach Paul Grayson said: "We're so disappointed for Steve and will be working to help his recovery."
Thompson has been suffering on-going neck trouble but took a heavy blow in the Heineken Cup loss to Biarritz.
At that stage the Northampton and England medical teams agreed that the 28-year-old required an eight-week rest from playing and training.
The plan had been to reassess him after that - but the decision has now been taken that he needs an operation.
It leaves Thompson, who has won 47 caps, facing an anxious wait to discover whether the injury will end his career.
Thompson has not played for England since the 2006 Six Nations but had been widely expected to regain the hooker's jersey for this year's competition before injury struck.
England coach Brian Ashton was quick to express his disappointment and sympathy.
"I am bitterly disappointed for Steve and his club," he said.
"I hope the operation is successful and that he makes a full recovery."
Leicester's George Chuter is now in pole position for the World Cup after starting the Six Nations victories over Scotland and Italy, when Bath's Lee Mears has been on the bench.
"It is a shame about Steve," Chuter told BBC Sport on Wednesday. "I get on very well with him, he is a nice guy and has been a great servant to English rugby.
"All the best to him and hopefully we will see him back soon."
Sale's Andy Titterell, Leicester's James Buckland, Thompson's Saints understudy Dylan Hartley and David Paice of London Irish have also started for the England Saxons over the last 12 months.