Ollie Chessum faces a race against time to make the World Cup after dislocating his ankle.
The Leicester lock will go under the knife on Monday, and faces a five to six month recovery time.
Head coach Steve Borthwick insisted England remain hopeful the engine room powerhouse can recover in time for the global battle in France.
Chessum has been one of England’s top performers in a breakthrough Six Nations, and England could well do with his physicality and set-piece acumen in the autumn.
“We are very hopeful he will have that opportunity to be fit for the World Cup,” said Borthwick.
“He’s a great player and a brilliant young man, he’s going to do everything in his power to get back on the field as soon as possible.”
New boss Borthwick already rates Chessum as among his most important performers.
“I think you’ve seen the growth of a player who looked at home at this level. I was chatting to him this morning and the determination he has to be back on the field and back in an England shirt is quite immense.
“He will have the opportunity to be fit and back on the field in readiness (indistinct) for the Rugby World Cup.”
England have enough problems on their plate already after last weekend;s record home defeat, the 53-10 hammering by France.
Borthwick’s men now face world number one side Ireland in Dublin on Saturday, where the hosts will be gunning to complete a second Grand Slam in five years.
The England boss admitted there had been some frank conversations this week.
“Last week was not good enough, there have been a number of forthright conversations in review of that game.
“We’ve got to test our capabilities against the number one side in the world. And our performance needs to improve substantially.”
London Irish speedster Henry Arundell will make his full Test debut in one of England’s highest pressure games.
Borthwick’s faith speaks volumes on Arundell’s prodigious talent and calm demeanour.
“Henry Arundell has an enormous future in front of him,” said Borthwick.
“He is right for this game. We’ve already seen glimpses of his talent at this level, and he’s an incredibly exciting player.”
