Forwards Maro Itoje and Dylan Hartley will join up with the England squad to continue their rehabilitation from injury ahead of the potential Six Nations title decider against Wales on Feb. 23.
Lock Itoje and prop Hartley have not been named among the 25-strong group selected by Eddie Jones for England's three-day training camp in London, but will be on location recovering from knee and ankle injuries, the Rugby Football Union confirmed.
With prop Mako Vunipola ruled out for the remainder of the tournament, Jones has included Exeter Chiefs' Ben Moon with Leicester's Ellis Genge providing additional cover at loosehead.
Four players -- Dan Cole (Leicester Tigers), Dan Robson (Wasps), Joe Cokanasiga (Bath) and Mike Brown (Harlequins) -- have been released to play for their clubs over the weekend.
Prop Cole, who is the only one to be have been involved in both of England's Six Nations games so far, could feature against Saracens on Saturday while scrumhalf Robson, who won his first cap against France, could play for Wasps against Bristol Friday.
Cokanasiga is clear to take the field against Newcastle and Brown is also available for Quins against Worcester.
Exeter centre Ollie Devoto was a surprise inclusion in the squad, having previously only played five minutes for England as a replacement against Wales in 2016.
Jones will update his squad next week before naming his starting XV on Feb. 21.
England squad (provisional)
Forwards: Luke Cowan-Dickie (Exeter Chiefs), Tom Curry (Sale Sharks), Ellis Genge (Leicester Tigers), Jamie George (Saracens), Nathan Hughes (Wasps), George Kruis (Saracens), Joe Launchbury (Wasps) Courtney Lawes (Northampton Saints), Brad Shields (Wasps), Kyle Sinckler (Harlequins), Billy Vunipola (Saracens), Ben Moon (Exeter Chiefs), Harry Williams (Exeter Chiefs), Mark Wilson (Newcastle Falcons)
Backs: Chris Ashton (Sale Sharks), Elliot Daly (Wasps), Ollie Devoto (Exeter Chiefs), Owen Farrell (Saracens), George Ford (Leicester Tigers), Jonny May (Leicester Tigers), Jack Nowell (Exeter Chiefs), Henry Slade (Exeter Chiefs), Ben Te'o (Worcester Warriors), Manu Tuilagi (Leicester Tigers), Ben Youngs (Leicester Tigers) (Reporting by Hardik Vyas in Bengaluru Editing by Christian Radnedge)