England suffered a blow on the eve of their Autumn Nations Cup final against France when Mako Vunipola was ruled out with calf trouble.
The loosehead prop suffered the injury during last weekend's pool win away to Wales and has not regained fitness in time for Sunday's match at Twickenham.
Ellis Genge has now been promoted from the bench into England's front row, with Joe Marler filling the vacancy among the replacements.
Vunipola once again became England's first-choice loosehead when Marler missed the Six Nations resumption with a knee injury after the coronavirus pandemic had brought rugby union to a shuddering halt.
"Mako has been struggling throughout the week and has barely trained. His Achilles is pretty sore," Vunipola's fellow Saracens front-row forward Jamie George said Saturday.
"It's a big loss missing a player of Mako's calibre, but what an exciting prospect having Ellis step in," the England hooker added. "We won't lose much in terms of energy!"
France are the only team to have beaten Six Nations champions England this year, winning 24-17 in Paris in February.
But their starting XV for the inaugural Nations Cup final features just 68 caps, following an agreement between the French Rugby Federation (FFR) and the country's Top 14 clubs limiting players to three appearances in the revised end-of-year Test schedule.
- 'Not the Mickey Mouse Cup' -
The Nations Cup only came into being when major southern hemisphere countries cancelled planned tours of Europe because of Covid-19.
But George said there was no questioning England's desire to triumph in their first final since South Africa beat them 32-12 to win last year's World Cup in Yokohama.
"No one in this environment is calling it the Mickey Mouse Cup and that's all that matters really," said George ahead of a match that will be played in front of 2,000 fans as spectators return to Twickenham for the first time since the pandemic.
"The end goal of this campaign was to be in the position to win this trophy. I've been lucky enough to win a few at Saracens. The more experience of finals rugby you have, the better you get at them."
The British and Irish Lions international added: "This time last year we (England) played in a big final that didn't go our way, hopefully it can be different this time around. Lift the trophy and look forward to the Six Nations in a couple of months time."
"Having fans there certainly will give us a lift. My parents are able to come to the game, which means a lot to me."
Revised England team (15-1)
Elliot Daly; Anthony Watson, Henry Slade, Owen Farrell (capt), Jonny May; George Ford, Ben Youngs; Billy Vunipola, Sam Underhill, Tom Curry; Joe Launchbury, Maro Itoje; Kyle Sinckler, Jamie George, Ellis Genge
Replacements: Luke Cowan-Dickie, Joe Marler, Will Stuart, Jonny Hill, Ben Earl, Dan Robson, Max Malins, Joe Marchant
Coach: Eddie Jones (AUS)