Maro Itoje and Elliot Daly will travel to Edinburgh with England's squad for their RBS 6 Nations clash with Scotland on Saturday.
The uncapped duo will accompany the 23 selected by Eddie Jones last week as reserves, although Itoje could yet feature on the bench at Murrayfield.
England are monitoring the fitness of Courtney Lawes, who has been struggling with a hamstring injury, and will give him until Thursday to prove he can play.
If the Northampton lock fails to be given the all clear, Itoje will be promoted into the matchday 23 as back-up for Joe Launchbury and George Kruis.
Itoje was named man of the match in Saracens' victory over Bath on Saturday and forwards coach Steve Borthwick believes the 21-year-old will be an outstanding international.
"Hopefully he has a huge future in front of him," Borthwick said.
"He has shown the potential he has and our job now is to help him develop and learn so that he can be an international for England for a long time.
"He's a young guy and now that he's spending time around the squad, hopefully it will lay the foundation for an England career that will last a lot of years.
"We don't need to be rushing him, we just need to make sure that he's absolutely ready to go.
"Being able to play six and second row is helpful in many ways and it will be interesting to see how he develops.
"He certainly has the athleticism to operate at six and that's a huge asset for him."
England's 23-man squad for RBS 6 Nations match against Scotland on Saturday: Forwards: D Cole (Leicester), J Clifford (Harlequins), J George (Saracens), D Hartley (Northampton, captain), J Haskell (Wasps), P Hill (Northampton), G Kruis (Saracens), J Launchbury (Wasps), C Lawes (Northampton), J Marler (Harlequins), C Robshaw (Harlequins), B Vunipola (Saracens), M Vunipola (Saracens).
Backs: M Brown (Harlequins), D Care (Harlequins), O Devoto (Bath), O Farrell (Saracens), G Ford (Bath), A Goode (Saracens), J Joseph (Bath), J Nowell (Exeter), A Watson (Bath), B Youngs (Leicester).
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