Ronaldo left Madrid for Juventus over a year ago - and Calderon says the club is yet to recover.
He told AS: "He should never have left, it's amazing that he was let go.
"It's impossible to do without such a player. 60 goals per season ... no player can bring you such a guarantee. He is irreplaceable, just like (Lionel) Messi.
"I am outraged that this may have happened, while (president) Florentino (Perez) keeps saying that Cristiano's signature was the best of his mandate."