Could Cristiano Ronaldo return to Manchester United? Ramon Calderon thinks that this may be a possibility in the future.

The former Real Madrid president, who was the man responsible for luring Ronaldo away from Manchester United back in 2009, recently opened up about how he views Ronaldo's career winding up. And he does not see the superstar retiring at the Santiago Bernabeu.

"I do not think he [Ronaldo] will finish his career at Real. I feel that one day he will return to England," said Calderon, according to ESPN. "In Madrid, he is pleased with the city and the fans."

However, he noted that the reason for Ronaldo's likely departure is his relationship to current Madrid president Florentino Perez.

"I think his relationship with [Real president] Florentino Perez is not as good as it was with Alex Ferguson at Manchester United," he added. "Ronaldo loves father figures. With Florentino, he does not have that rapport. The relationship is bad or actually non-existent. He stays at Real despite the chairman."

Ronaldo is known to have asked Madrid to give him an extra season with Manchester United out of respect for Alex Ferguson; even though that never happened (due to Madrid's fear of losing Ronaldo), that gesture was always an emblem of Ronaldo's respect for his former manager.

Calderon also added that Ronaldo could potentially leave whenever he feels like it.

"I was afraid he was going to leave [in the summer] because he is our best player. I have the feeling that Cristiano has a clause in his contract allowing him to leave when he wants," said Calderon.

Is Manchester United the future of Ronaldo? The story dominated headlines throughout the summer and the superstar even confirmed that he considered a return prior to his contract extension.