Experienced England hooker Luke Cowan-Dickie will miss this autumn's World Cup in France with a shoulder injury.
Uncapped number eight Tom Willis is included in the 41-man training squad, but Gloucester-bound back-row forward Zach Mercer misses out.
There is no place for Northampton scrum-half Alex Mitchell, with Danny Care, Ben Youngs, and Jack van Poortvliet the only remaining nines.
Saracens' Owen Farrell will be captain at the tournament.
Head coach Steve Borthwick will confirm his final 33-man group on 7 August.
England play four warm-up matches through August, before opening their World Cup campaign against Argentina in Marseille on 9 September.
"We hope today's announcement is the start of something special for our supporters, who I know are eagerly anticipating the tournament as much as we are," said Borthwick.
Willis edges out Mercer
Tom Willis, who is moving to Saracens for the new season, has impressed since joining Bordeaux-Begles in November following the collapse of Wasps, and joins brother Jack in the squad.
However the omission of Mercer comes as a major surprise given England's lack of depth at number eight and his performances for Montpellier in the French Top 14, where he won player of the season in 2022.
It leaves Tom Willis in pole position to make the final squad given the knee injury suffered by Billy Vunipola in April, who remains in the camp as he continues his rehabilitation with hopes of returning in August.
At hooker, Cowan-Dickie's absence will be keenly felt, with all other options bar Jamie George lacking experience.
Cowan-Dickie tweeted "everything happens for a reason" after the squad announcement, adding: "Gutted is an understatement, but I'll be back."
Newcastle's Jamie Blamire and Saracens rookie Theo Dan - a star of the Premiership final - are both included, while Harlequins' Jack Walker continues his recovery from injury.
"Despite all his incredible work and progress, Luke's shoulder has not improved sufficiently for him to be considered for selection for the World Cup," added Borthwick.
"We wish him a swift recovery and hope to see him back playing very soon."
Dan is one of five uncapped players in the squad, along with Tom Willis, ex-London Irish flanker Tom Pearson, Quins flyer Cadan Murley and Gloucester prop Val Rapava-Ruskin.
Care set to make final cut
Borthwick's selections at scrum-half also come as a surprise, with Mitchell, a regular during the Six Nations, axed from the group.
There is also no place for Sale's Raffi Quirke, Bristol's Harry Randall, or Bath's Ben Spencer.
With only three number nines left, it means Care has an excellent chance of making the final cut at the age of 36.
The 87-cap Quins veteran made his long-awaited return to Test rugby on the 2022 summer tour of Australia, but didn't feature in the following autumn or the recent Six Nations.
"We're excited to be able to bring a full training squad together for the first time and focus on the next stage of our World Cup preparations," said Borthwick.
England training squad
Forwards: Jamie Blamire, Dan Cole, Tom Curry, Theo Dan, Alex Dombrandt, Ben Earl, Ellis Genge, Jamie George, Jonny Hill, Maro Itoje, Courtney Lawes, Lewis Ludlam, Joe Marler, George Martin, Tom Pearson, Val Rapava-Ruskin, David Ribbans, Bevan Rodd, Kyle Sinckler, Will Stuart, Sam Underhill, Jack Willis, Tom Willis.
Backs: Henry Arundell, Danny Care, Joe Cokanasiga, Elliot Daly, Owen Farrell, George Ford, Max Malins, Joe Marchant, Jonny May, Cadan Murley, Guy Porter, Henry Slade, Marcus Smith, Freddie Steward, Manu Tuilagi, Jack van Poortvliet, Anthony Watson, Ben Youngs.