The former Blancos chief believes that the Portuguese attacker's problems with the club were not financially motivated, and praised Tuesday night's Barcelona-beating performance
The ex-Manchester United attacker has been linked with a move away from the Santiago Bernabeu in the summer, with Paris Saint-Germain repeatedly mentioned as a potentially interested party.
However, both the club and the player have dismissed the talk as pure speculation, and Calderon believes current Blancos chief Florentino Perez will do everything in his power to hold on to Ronaldo.
"There is no debate: no president would want to have to sell Cristiano," he told reporters after the annual Challenge Nacex golf tournament.
"I do not think [Ronaldo’s] problem is financially motivated. Besides, I know him well, as I was the one who brought him to Madrid."
Los Blancos are riding high following their 3-1 demolition of Barcelona at Camp Nou on Tuesday - in which Ronaldo starred and scored twice - and Calderon praised the club he used to run as well as head coach Jose Mourinho.
"Real Madrid were very good against Barcelona,” he said. "Ronaldo was like a bull.
“Mourinho is a good coach and is now grateful to the fans, and more relaxed."
Madrid’s next match is against Barcelona on Saturday before the reigning Liga champions face Sir Alex Ferguson’s side in the second leg of their last 16 clash at Old Trafford, with the tie poised at 1-1.