Northampton Saints hooker Dylan Hartley has failed to recover from a knee injury in time and was left out of England head coach Eddie Jones' first training squad for the upcoming World Cup in Japan which was announced on Thursday.
Hartley, who captained England to back-to-back Six Nations titles in 2016 and 2017, has not played since December.
The first training camp will be held at Pennyhill Park (June 23-27) followed by another at the Lensbury (30 June 30 to 4 July).
"The first two training camps are designed to improve individual players' fundamentals to allow them to compete for a place in the World Cup squad," said Jones.
Experienced scrumhalf Danny Care and flanker Chris Robshaw also missed out on the 29-man training squad after slipping down the England pecking order.
Care, who has 84 England caps, did not feature in this year's Six Nations, while Robshaw has not played for his country since having knee surgery in October.
Harlequins number eight Alex Dombrandt, Northampton Saints flanker Lewis Ludlam and former England Sevens player Ruaridh McConnochie were among those who received their first call-up.
Saracens lock George Kruis and team mate Mako Vunipola will be part of the camp for medical treatment.
The squad comprises players who were not involved in last month's English Premiership semi-finals because all those who were have been put on mandatory rest for five weeks.
Players from losing semi-finalists Gloucester and Northampton Saints will join the camp next week and Jones will name his final training party, including players from Premiership finalists Exeter Chiefs and Saracens, on 4 July.
The Rugby World Cup kicks off on 20 September with England facing Tonga in their opening Pool C encounter in Sapporo two days later
England training squad
Forwards: Dan Cole (Leicester Tigers), Tom Curry (Sale Sharks), Alex Dombrandt (Harlequins), Tom Dunn (Bath Rugby), Charlie Ewels (Bath Rugby), Ellis Genge (Leicester Tigers), Joe Launchbury (Wasps), Lewis Ludlam (Northampton Saints), Val Rapava Ruskin (Gloucester Rugby), Nick Schonert (Worcester Warriors), Brad Shields (Wasps), Kyle Sinckler (Harlequins), Jack Singleton (Worcester Warriors), Sam Underhill (Bath Rugby), Mark Wilson (Newcastle Falcons).
Backs: Chris Ashton (Sale Sharks), Mike Brown (Harlequins), Joe Cokanasiga (Bath Rugby), Elliot Daly (Wasps), George Ford (Leicester Tigers), Jonathan Joseph (Bath Rugby), Jonny May (Leicester Tigers), Ruaridh McConnochie (Bath Rugby), Dan Robson (Wasps), Marcus Smith (Harlequins), Ben Te'o (Worcester Warriors), Manu Tuilagi (Leicester Tigers), Anthony Watson (Bath Rugby), Ben Youngs (Leicester Tigers).