Lancaster keeps options open
Manu Tuilagi, Brad Barritt and Billy Twelvetrees have all been included in a 25-man England squad to face Ireland in the Six Nations on Sunday.
England coach Stuart Lancaster has kept his midfield options open by including the trio in his plans for Dublin.
Tuilagi is fit again after missing England's Calcutta Cup victory over Scotland and Lancaster must decide whether to bring the powerful Leicester centre straight back into the starting line-up.
Uncapped Wasps number eight Billy Vunipola is also in contention to replace Ben Morgan, who has not been included in the travelling party after suffering a sprained ankle on Saturday.
The Gloucester forward will remain with the England squad to continue treatment and, although not officially ruled out, a team spokesman said he was "unlikely to figure" at the Aviva Stadium.
Vunipola, the dynamic younger brother of England prop Mako, came through both training sessions on Tuesday after recovering from an ankle problem.
The 21-year-old will compete with Leicester's Thomas Waldrom for a place in the final 23-man match-day squad, most likely on the bench.
James Haskell is expected to be promoted into the starting line-up at blindside flanker, with Tom Wood set to shift across the back row to replace Morgan at number eight.
England are permitted under the terms of their agreement with Premiership Rugby to travel to away games with two additional players to their 23-man match-day squad.
Lancaster will confirm his midfield and back row selections when he finalises the England line-up on Friday morning.
Of those definitely missing out, Northampton full-back Ben Foden has been released for a second straight week with David Strettle again preferred.
Lancaster's midfield decision is possibly the toughest selection poser of his reign.
England are a demonstrably more potent attacking force with Tuilagi in the side and his partnership with Barritt was central to the record victory over New Zealand last December.
Twelvetrees enjoyed an eye-catching debut against Scotland when he came into the team at inside centre with Barritt shifting out of his natural position into the 13 jersey.
That led to immediate calls for Tuilagi and Twelvetrees to start together, an attack-minded choice that would sacrifice Barritt's key contribution as the team's defensive leader.
England could be reluctant to omit those key qualities against an Irish attack that includes the bewitching skills of Brian O'Driscoll and Jonathan Sexton.
Lancaster has one more training day to finalise his selection before announcing his team on Friday. The squad have Thursday off.
Vunipola, a dynamic and powerful ball carrier, is highly regarded by the England management after exploding onto the scene with Wasps this season.
If he was to win selection on the bench, England will go into the game with two sets of brothers in the 23-man squad - with Billy and Mako Vunipola joining Ben and Tom Youngs.
England squad - BACKS: C Ashton (Saracens), B Barritt (Saracens), M Brown (Harlequins), D Care (Harlequins), O Farrell (Saracens), T Flood (Leicester Tigers), A Goode (Saracens), D Strettle (Saracens), M Tuilagi (Leicester Tigers), B Twelvetrees (Gloucester Rugby), B Youngs (Leicester Tigers).
FORWARDS: D Cole (Leicester Tigers), D Hartley (Northampton Saints), J Haskell (London Wasps), J Launchbury (London Wasps), C Lawes (Northampton Saints), J Marler (Harlequins), G Parling (Leicester Tigers), C Robshaw (Harlequins, capt), B Vunipola (London Wasps), M Vunipola (Saracens), T Waldrom (Leicester Tigers), D Wilson (Bath Rugby), T Wood (Northampton Saints), T Youngs (Leicester Tigers).