The Brazilian Football Federation says no English club has been in contact about trying to sort out a medical for Lucas Moura during the Olympics, while Sao Paulo say they will fight hard to keep him.
The highly-rated 19-year-old has attracted the attention of several clubs in Europe this summer and it is understood that Manchester United are in pole position to secure his signature.
However, Brazil's FA (CBF) has dismissed reports of Moura being given permission to undergo a medical with United.
"We haven't received any request from an English club regarding that," the CBF told Globo Esporte.
"In case we do receive such a request, we won't allow the player to leave Brazil's training to undergo the medical."
Moura's agent, Wagner Ribeiro, has also insisted it is too early to talk about the player completing a transfer anywhere.
He said: "I don't talk about factoids. This news about the selling of Lucas is not true."
Sao Paulo maintain that no talks are currently taking place over a proposed move as they look to hold on to the winger, although they admit it would be wrong to rule out a departure.
Vice-president Joao Paulo de Jesus Lopes told Lancenet: "He will certainly return to Sao Paulo.
"There is no negotiation going on. As we have already said it's very hard for him to leave during the current transfer window.
"We have no interest in selling him but Sao Paulo are not stupid. We know that in certain situations you can't say no.
"But such kind of offer hasn't come yet."