Two players have already pulled out of the squad - Manchester United midfielder Michael Carrick, who has a hip problem, while Tottenham striker Jermain Defoe will have a scan on an ankle injury on Monday.
Meanwhile, Liverpool striker Daniel Sturridge is a doubt after sustaining a thigh injury in Sunday's 2-2 draw at Manchester City.
The 23-year-old, who has just four senior caps, picked up a knock in the first half shortly after scoring to level the match at one apiece.
Liverpool boss Brendan Rodgers said: "I think he will be a doubt for the game on Wednesday, which is unfortunate because he was terrific today."
England manager Roy Hodgson remained upbeat, despite having to face the five-time World Cup winners without some of his experienced stars.
"I'm pleased with the squad we've got and I hope we won't suffer too much from today's or Saturday's games," Hodgson told Sky Sports.
"I'll then have at least the nucleus of players I chose to play the game. I think we've got some good players ourselves, but we know how good Brazil are.
"I'd like to think we'll give them a good game and it would be lovely to start the year with a victory."
The Football Association confirmed several other withdrawals from the England U21 squad ahead of their game with Sweden.
"Michael Carrick (hip) and Jermain Defoe (ankle) have both withdrawn from Roy Hodgson's squad to face Brazil," the FA statement read.
"Phil Jones, Raheem Sterling, Nathaniel Clyne and Ryan Bennett are also missing from the Under-21 group to face Sweden at Walsall through a mixture of injury and illness.
"No replacements have been called in to either squad at this time."