The Chelsea and international skipper is the latest injury concern for Capello after he missed Friday's session in Doha ahead of the friendly in Qatar.
However, the Italian coach believes Terry will be okay to face the five-time world champions.
- England home
- Lampard out for three weeks
"John is our skipper - he will always play when he can," he said. "He is really important for us and I think he will be okay."
England are already without a raft of senior players, with the likes of Rio Ferdinand, Steven Gerrard, Frank Lampard, David Beckham, Emile Heskey, Ashley Cole and David James all absent.
But an upbeat Capello believes their absence opens the door for a number of fringe members of his squad to stake a claim for a World Cup place.
"It will be a very interesting game. I can check a lot of different players in different positions," he added.
"To see what they can do against Brazil will be really important. They are probably the best country in the world.
"The hardest selection problem is deciding the centre-back pairing. If Terry makes the first eleven then I must decide who to partner Wayne Rooney with."
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