Ronaldo is reportedly ready to quit the club after being accused of tax fraud .
Calderon was at the Bernabeu when Real signed the 32-year-old from United and believes Los Blancos may struggle to change his mind over a move.
“I think it is very difficult. I had the same situation with Manchester United when he wanted to leave and I signed him. He said ‘I want to leave’ and that was that,” Calderon told BBC Radio 5 live.
“The same year I had the problem with Robinho and he wanted to leave.
“As a president you can’t do anything other than let him go and get the best deal possible.
“I hope he hasn’t decided to leave but if he has already made his mind up, it will be difficult to change the situation.
Calderon also admitted a return to Old Trafford could be on the cards.
“Very few clubs can meet his expectations. Not because they can’t pay the money but because they need to offer him the possibility of winning titles and personal awards,” he added.
“The relationship in Madrid wasn’t the best but that doesn’t mean he doesn’t want to go back to Manchester where he is very grateful of what happened.
“He delayed his move to Madrid for a year because Ferguson was like a father to him. He loved the club, the fans, the city and I don’t rule out a move back.
“I am sure he will stay in Europe. I don’t see him playing in China or the Middle East. He is not that type of player. He has three or four more years to be a top, top player and he would like to keep winning titles, anywhere he goes.” PLACE YOUR TEXT ADVERT BELOW:>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> How I TOTALLY Got Rid Of my POT BELLY,excess Fat and Overweight In just 2weeks.. Click HERE for Details.