FIFA's disciplinary committee is studying the challenge that led to Brazil's star player Neymar suffering a fractured vertebra to decide on action against Colombia's Juan Zuniga.
The Colombia defender caught Neymar with a knee in his back in a full-blooded challenge that went unpunished during Brazil's 2-1 quarter-final win.
FIFA head of media Delia Fischer said: "The disciplinary committee is analysing the matter. The spirit of fair play is very important and we want to avoid difficult things on the field of play."
Ronaldo, Brazil's former World Cup-winning striker, believes Zuniga had intended to hurt Neymar.
He told a news conference in Rio de Janeiro: "The challenge was a very violent one - I believe there was an intention by the Colombian player to cause some harm.
"I don't think it was normal football play, I don't know whether he had planned this beforehand but I do believe it was very aggressive, very violent."
Zuniga defended the challenge after the match, saying he had not deliberately hurt Neymar.
He said: "It was a normal move, I never meant to hurt a player. I was on the field, playing for the shirt from my country, not intending to injure anyone. I was just defending my shirt."