The 27-year-old hobbled out of training on Wednesday after suffering a leg strain.
Despite fears over his fitness, the forward expects to be available for tomorrow night's encounter with the Mexicans.
"I can play," he is quoted as saying by Sky Sports News. "We have to face everything in a World Cup and I hope this is no big deal.
"I'll have treatment and try to be fit for Tuesday so that I can help the national team. Of course this worries me but I am in the hands of great professionals."
Brazil won their opening match of the tournament last week thanks to a 3-1 victory over Croatia.