"I had offers from City, Chelsea and Milan," Leon told Onda Cero.
"Some wanted to sign me in the winter but Mourinho didn't let me go."
Leon faced criticism from Mourinho for his effort in training.
"He's not called up for one game and it seems like you are talking about a great player.
"When he works how I want him to, he will play, and when he doesn't, it will be harder for him to play."