The 24-year-old midfielder was loaned out to Getafe in the summer after failing to get a chance at the Santiago Bernabeu under the Portuguese coach.
Pedro Leon, who made just five starts for Madrid last season, believes he was treated unfairly while at the club, but chose to focus his criticism on Mourinho.
"I felt humiliated at Madrid," he told Cadena SER. "I am not aware of doing anything wrong. I did all I could, I was professional, I worked hard.
"I think that everyone who is under a contract should be treated the same way, but I do not have any reason to complain about the club."
The former Spain Under-21 international went on to lament the remarks made last season by Mourinho, who said Pedro Leon was "not [Zinedine] Zidane, nor [Diego] Maradona", when pressed about his reasons not to include the midfielder in his plans.
"The way in which those comments were made hurt me more than the words themselves," Pedro Leon noted.
"There are many ways to say things, you can say whatever you want, but you can do it in many different ways."
Pedro Leon then revealed that Chelsea enquired about him and that, despite not being an option for Mourinho, the Portuguese coach blocked his transfer to Stamford Bridge.
"Chelsea are one of the biggest clubs in Europe and of course I was excited about the possibility," he added.
"The coach gave me his opinion and told me he would not let me go. He told me I would not play much in London.
"Honestly, my opinion is that Chelsea's coach [then] was Carlo Ancelotti, not him."
Pedro Leon joined Madrid from Getafe in July 2010 for €10 million.
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