Ronaldo has declared he is close to joining Manchester City.
The South American admitted to arriving at Flamengo overweight, saying he had put on more than a stone, to go over 15 stone.
City executive chairman Garry Cook recently met the player, and club officials carried out medical checks on Ronaldo's knee.
But City have stressed they will not be completing a deal for the three-time former FIFA world player of the year.
Ronaldo, who last played for his country in 2006, is optimistic he can return to the summit of the game and even play in the 2010 World Cup in South Africa.
"I really want to be there, it would be very nice," he said. "But first I have to recover properly.
"I am working hard to return to my old self and I do it because I love football.
"I could stay at home, playing with my friends but I love everything that has to do with a match.
"I like seeing the fans, the motivation, feeling the pressure of the tournament.
"When I am exhausted after a training session, I always think someone is going to pay for all this effort. I believe the defenders are going to pay."