Lancaster added: "[Eastmond replacing Twelvetrees] is as close to a straight swap as there can be. They are different physically but Kyle can definitely carry and he can distribute and pass pretty much like Billy can.
"The timing of his passing, the range of passing he has got is exceptional and the challenge is to translate that into a game.
"The way we want to play should allow him to express himself and show those talents in the game and it is the next step for him to prove he can do it."
"What strikes me about Marland is his workrate off the ball and his desire to get his hands on the ball," Lancaster said. "He is not the type of guy who is just going to stand on his wing and wait for the ball to come to him."
England scored four tries last week on the back of a dominant forward display in Salta and Lancaster knows they will need a repeat performance to give their backs a platform.
"There's definitely going to be a reaction from Argentina and what laid the foundation for our performance last week was our set-piece," Lancaster said.
"Our scrum was good, our lineout was good, we turned over their lineout and created turnover ball and counter-attacking opportunities."
Prop David Wilson and lock Joe Launchbury have not trained fully this week but both are set to play.
Mike Brown (Harlequins); Christian Wade (Wasps), Jonathan Joseph (London Irish), Kyle Eastmond (Bath), Marland Yarde (London Irish); Freddie Burns (Gloucester), Lee Dickson (Northampton); Joe Marler (Harlequins), Rob Webber (Bath), David Wilson (Bath), Joe Launchbury (Wasps), Dave Attwood (Bath), Tom Wood (Northampton, capt), Matt Kvesic (Worcester), Ben Morgan (Gloucester).
David Paice (London Irish), Henry Thomas (Sale Sharks), Paul Doran-Jones (Northampton), Courtney Lawes (Northampton), Billy Vunipola (Wasps), Richard Wigglesworth (Saracens), Stephen Myler (Northampton), Ben Foden (Northampton).
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