The Al-Nassr star is ready to sign for a club competing in the USA-based tournament this month.
And Bittencourt, speaking on Setor Sul, revealed: "I don't have a close relationship with Jorge Mendes, but when I call him, he answers.
"He was Cristiano Ronaldo's agent all his life, but today he is no longer. In any case, I contacted him to find out if there was any possibility that Cristiano Ronaldo would play the Club World Cup with us.
"He was very clear with me and said that at the moment there is no interest from Ronaldo to play in Brazilian football. I told him that Fluminense has the colors of the Portuguese flag, that it would be great to play in Brazil, it would be a dream for our fans.
"But you can't say that we have put a concrete offer on the table."