The agent of Porto striker Hulk claims the club rejected an €80m (£70m) offer for the player.
The 25-year-old signed a new contract in May which included a €100m (£88m) release clause.
"I would be lying if I said no proposals have emerged to sign Hulk," Teodoro Fonseca told Portuguese newspaper Record.
"I think the highest bid was €80 million, but Porto did not even want to negotiate."
The forward has been linked with a number of clubs, including Chelsea, after scoring 36 goals in 70 games for the reigning Portuguese champions.