England's medical staff have been astonished by the speed of the midfielder's recovery from an ankle injury that convinced Capello he was out of the finals.
But his chances of starting in Rustenburg are slim because Capello won't put a player crucial to his plans at any risk.
Look out for Sportsmail's live updates on England's practice match against Platinum Stars from 3pm Raring to go: Gareth Barry's recovery from injury has been remarkable, but Fabio Capello is set to rest him for USA
The same goes for 39-year-old goalkeeper David James, who was back in training on Sunday but could be ruled out by a slight knee problem. That would let in Robert Green or Joe Hart, with the West Ham keeper just ahead, even though Hart is impressing more in training.
Matthew Upson has been sick for the past couple of days and will not play in Monday's game against the Platinum Stars. Ledley King might not play either if Capello thinks it could jeopardise his chances of playing on Saturday.
Hands on: Robert Green could start for England against USA on June 12
Most players are expected to get some time on the field on Monday and Wayne Rooney will certainly be keen to play. In training on Sunday he was said to have looked sharper than he has in the past three months.
Meanwhile, Rio Ferdinand fears he will struggle to be fit for the start of the new season. Initial reports said the England and Manchester United captain would be sidelined for four to six weeks with the medial ligament injury that has forced him out of the World Cup.
Pain game: Injured Rio Ferdinand will return to England after watching the opening Group C clash against USA
But Ferdinand thinks it could be nearer eight weeks before he can train again, so serious is the knee injury.
He will stay to watch England play the US in their opening game and then return home.
Click here to sign up for Sportsmail's daily World Cup emailMore than just a bunch of cowboys: Meet South Africa's Platinum StarsEngland v USA ref Carlos Eugenio Simon had six-week 'corruption' banMy Dad is top of the crocks! King's knees are so bad he can't even play with his sonWe're just all over the place with these balls, says USA keeper Howard