Madrid suffered back-to-back losses against bitter rivals Barcelona to crash out of the Copa del Rey and lose further ground in La Liga, before going down 4-1 to Ajax in one of the most humbling results in their history.
"It is an erratic and whimsical president who has brought us to this situation", he said, further piling the pressure on the club president Florentino Perez.
Calderon told BBC Radio 5 Live: "I know that this morning the president [Florentino Perez] called Zidane to ask him back, he said not now".
Rangers qualified for the group stage of the Europa League for the first time in eight years this season, but finished third behind Villarreal and Rapid Vienna.
Bale ended the match with a sprained right ankle, but alongside Costa Rica goalkeeper Keylor Navas and Spanish defender Sergio Reguilon, trained on Thursday inside the facilities.
But Ramos is alleged to have held what could perhaps be described as crisis talks the following day, calling a players meeting from which coach Santiago Solari was apparently excluded.
Madrid president Florentino Perez has always been fond of Mourinho, but the Portuguese coach is certainly not the only candidate to replace Solari.
Zinedine Zidane, who left in the summer after guiding Madrid to three Champions League titles on the trot, was also spoken to about the role while Germany manager Joachim Low was considered too.