Exeter Chiefs prop Ben Moon and Leicester Tigers full-back Jordan Olowofela have been called into the England training squad in Bristol for the camp that runs until Tuesday, September 25.
The 29-year-old prop replaces Joe Marler (Harlequins) who has withdrawn from the squad for personal reasons.
In addition, Nick Schonert (Worcester Warriors), Manu Tuilagi (Leicester Tigers) and Ben Youngs (Leicester Tigers) have not joined up with the squad due to injury. Olowofela has been called up as a replacement for Tuilagi.
Ahead of the Quilter Internationals in November an England squad will be named on October 18 before they fly to Portugal on October 24 to begin their final preparations for the four-Test series.
England will play South Africa (November 3), New Zealand (November 10), Japan (November 17) and Australia (November 24) at Twickenham Stadium.
England training squad
Forwards: Tom Curry (Sale Sharks), Jamie George (Saracens), Dylan Hartley (Northampton Saints), Nathan Hughes (Wasps), Nick Isiekwe (Saracens), Maro Itoje (Saracens), George Kruis (Saracens), Joe Launchbury (Wasps), Courtney Lawes (Northampton Saints), Zach Mercer (Bath Rugby), Ben Moon (Exeter Chiefs), Michael Rhodes (Saracens), Chris Robshaw (Harlequins), Brad Shields (Wasps), Kyle Sinckler (Harlequins), Billy Vunipola (Saracens), Mako Vunipola (Saracens), Harry Williams (Exeter Chiefs), Mark Wilson (Newcastle Falcons)
Backs: Chris Ashton (Sale Sharks), Mike Brown (Harlequins), Danny Care (Harlequins), Joe Cokanasiga (Bath Rugby), Elliot Daly (Wasps), Nathan Earle (Harlequins), Owen Farrell (Saracens), George Ford (Leicester Tigers), Alex Lozowski (Saracens), Jonny May (Leicester Tigers), Jack Nowell (Exeter Chiefs), Jordan Olowofela (Leicester Tigers), Dan Robson (Wasps), Henry Slade (Exeter Chiefs), Ben Te’o (Worcester Warriors)