Madrid have begun their courting of Hazard again ahead of the summer transfer window.
The Chelsea ace looks like Zinedine Zidane's No.1 target as he looks to ease the burden on Cristiano Ronaldo and Gareth Bale.
But Hazard is said to be happy at Chelsea and has told friends and family he will stay in London.
Real Madrid are stepping up their interest in Eden Hazard ahead of the summer
Eden Hazard has been in sensational form for Chelsea this season
And Calderon thinks the Blues will fight to keep Hazard and admits the player will have to force a departure to get a move.
"Chelsea aren't a selling club, so it wouldn't be easy, but as always it would depend on the wishes of the player," Calderon told TalkSPORT's Alan Brazil Sports Breakfast show. "If he wants to leave, he will leave – that's always the point.
"It's all about the player. The player must say, 'I want to leave and go to Real Madrid', and that will be the moment they start negotiating."
Chelsea fans panic on Twitter as Eden Hazard ruled out of Stoke clash
Sat, March 18, 2017
Chelsea fans panic on Twitter as Eden Hazard is reportedly ruled out of this afternoon's clash with Stoke City (3pm)
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Chelsea fans react as Eden Hazard is reportedly ruled out of clash with Stoke
And Calderon believes it would take a world record offer to persuade Chelsea to part with the 26-year-old.
Calderon added: "Chelsea will ask for a lot of money, I think that's what the situation will be at the end of the season.
"Chelsea knows quite well how much has been paid in the market over the last few years, with (Cristiano) Ronaldo, (Gareth) Bale and (Paul) Pogba – £100million is now the bar.
"That bar has been set by those transfers, so I think that's how much a club like Chelsea would be asking for and the economy at Real Madrid is healthy – I don't think that wouldn't be a problem for them."