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."