The two European nations go head-to-head in Salvador on Monday, with Real Madrid star Ronaldo limited in training recently due to a lingering knee injury.
The 2013 FIFA Ballon d'Or winner will be ready for the Germans, according to Carvalho, as the Sporting Lisbon man claimed Ronaldo was simply fatigued after a season that saw him star as a UEFA Champions League winner.
"In the beginning (of preparations), Ronaldo was tired because it was the end of the season," Carvalho said.
"But I think now he is 100 per cent fit and will give his best for the national squad.
"We have the best player in the world and we all know what he can achieve and we count on him to do all he can do for Portugal."
Despite claiming Ronaldo was fit, Carvalho refused to confirm whether the 111-capped man would be in Paulo Bento's starting XI.
"About Cristiano Ronaldo's physical condition, I have nothing to say, it is up to the doctors," Carvalho said.
"He is very important, he is our captain, he is the best player of the world.
"He will pass his experience on to the team. And I am sure he will help us to reach our targets."
Carvalho said while he and his team-mates learn from Ronaldo's presence in the squad, he does not want to emulate the attacker's game.
"Having the best player of the world in our team, it's obvious that we are going to learn from him," the 22-year-old said.
"We always hold him as an example to follow.
"I don't want to follow his footsteps though, I want to make my own path.
"Only in the future will we see how my future works out."
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