Owen Farrell is on course to start England's autumn opener against Argentina at Twickenham as he closes in on making a full recovery from concussion.
Farrell only has Thursday's return to play protocol to complete after being knocked out against Exeter on October 22, placing him on the brink of being able form a midfield trio alongside Marcus Smith and Manu Tuilagi for the first time in Sunday's clash.
The Saracens playmaker took a restricted part in training on Wednesday and England are increasingly confident he will be ready for the visit of the Michael Cheika-coached Pumas.
"Owen is just going through the last bits of his return to play but everything's gone according to plan so far," said attack coach Martin Gleeson.
"He looked good in training, full of enthusiasm. Just his normal self really."
England are keen to reprise the Smith-Farrell playmaking axis that was first seen last autumn only for successive ankle injuries to sideline the senior member of the attacking brains trust until the July tour to Australia.
England coach Eddie Jones is investing in the duo with next year's World Cup in mind, although they have fired only in glimpses as a partnership.
"Owen's partnership with Marcus is a big part of where we want to go as a team. They are four games in together and we want to build on that this autumn," Gleeson said.
Hooker Luke Cowan-Dickie and wing Jonny May have yet to be ruled out for the first of this month's Tests but they have not taken part in full training as they recover from respective knee and elbow injuries.
Less than a fortnight ago, May needed oxygen on the pitch after his arm contorted into an alarming position on club duty for Gloucester against London Irish.
"He's Jonny May! That's what he does. His healing powers are unbelievable," Gleeson said.
"He's in a good spot and is potentially available for this weekend, but we're not 100 per cent sure on that yet."