England's physios have been struggling to keep pace with Alex Oxlade-Chamberlain, who is making an extraordinary recovery from injury, according to James Milner.
Oxlade-Chamberlain's World Cup place had been in doubt after he strained a medial knee ligament during England's 2-2 draw with Ecuador in Miami.
The Arsenal winger raised hopes when he partook in a few sprints with fitness coach Tony Strudwick on Tuesday, and 24 hours later Oxlade-Chamberlain appears to be in even better condition.
Speaking at a Vauxhall-sponsored England fans' forum, Milner said Oxlade-Chamberlain was making good progress.
"It's great to see Ox about running," the Manchester City midfielder said.
"He obviously feared not long ago that it might be the end of his tournament, but the running he has been doing.
"He saw one of the physios off because he couldn't keep up with him so another physio had to come in and run the second part of the running with him, so he is running at good speed and coming along well."
Oxlade-Chamberlain's estimated recovery time was put at two to three weeks, meaning he would either be ready for England's second game against Uruguay, or their final Group D match against Costa Rica.
This weekend he will just be a spectator as England take on Italy in their first pool game in Manaus, where temperatures are set to soar above 30 degrees Celsius.
Unlike England, Italy have experience of playing in northern Brazil as they took part in last year's Confederations Cup, which included games in Recife and Fortaleza.
But Phil Jagielka, who was speaking alongside Milner in a terrace bar at the Sheraton Hotel in Rio de Janeiro, does not think that will give Italy the advantage over England, who prepared for Brazil with a week-long camp in the Sunshine State of Florida.
"Obviously they have had the experience of playing in these conditions but that's what going to Miami was about, to try and play in similar conditions," the England defender said.
"We feel we have done all we can preparation-wise. We have spent a lot of time planning the trips before the World Cup so we don't feel like we can be any more prepared."
Brazil showed why they are favourites for the World Cup by beating Spain 3-0 in the final of the Confederations Cup in the Maracana.
No European nation has ever won a major international competition in South America, but Milner sees no reason why that should faze England going into the tournament.
"I think records are there to be broken," the Yorkshireman said.
"No (European nation) has ever done it (win a World Cup in South America), but there is no reason why it can't be this year.
"From our preparation, we can't do anything more than we have done.
"I think the heat is getting pretty normal. We are getting to the stage where we are more worried about the cold when we go back to England than playing the first game in Manaus."
Milner, despite several probing questions from a crowd of around 50 England fans, refused to talk up the Three Lions' chances of winning the tournament.
But the 28-year-old does expect a couple of surprises at the tournament.
"It is hard to tell who will win it," he said.
"There are one or two teams who sneak through who you don't expect will get far.
"I think there could be a few surprise packages in there. Chile are probably not going to win it but I think they could go far.
"Brazil and Spain are two top teams and are always there or thereabouts, like Germany. It is hard to call one, and hopefully we are not too far away."