Billy Vunipola has been ruled out of the rest of the World Cup with a knee ligament strain.
The Saracens No.8 suffered the injury in last Saturday’s defeat to Wales and he has been replaced by Harlequins‘ Nick Easter.
On top of Vunipola’s injury, Courtney Lawes is a doubt for Saturday’s crucial clash against Australia with a knee injury.
“It’s so unfortunate for Billy – he’s worked really hard,” said England head coach Stuart Lancaster.
“He’s committed everything to the last three months but he is a young man with a bright future ahead of him and I know he’ll be an integral part of this team for years to come.
“Nick was unlucky to miss out on final selection. He is a specialist number eight and an experienced player. We know he will make a big contribution.”
Easter said: “The management said I was on standby and that anything can happen.
“It’s very unfortunate for Billy. He played very well against Wales and was a star of the Six Nations.”