The playmaker joined the club three years ago from Malaga in a deal worth 30 million euros but has failed to become a first-team regular in that time and he was whistled by Los Blancos fans during their 1-1 home draw with Eibar on Sunday.
"I have been two months, practically, without playing," he explained to Marca, with Tottenham, Manchester United and Malaga rumoured to be interested in his signature.
"It's difficult when you're training well and the boss does not put you in.
"But in the end it's my own fault. In the end it is me who is responsible. I want to see where I can improve to get in there.
"I am not going to give in easily. I know I will be a success. I don't know if that will be with Madrid -- I hope so. But if not, I will be a success somewhere else."
"I have two years left on my contract at Madrid," he said. "The club said nothing to me, and I didn't do anything to look for a move.
"They've not called me either to renew it, so I am relaxed. I look at the day-to-day, which is the important thing.
"I want to train hard, to show that I can be a starter. He [Zidane] told me it depended on my performances.
"There is a lot of competition and a team shape which is practically set in stone. It's possible that, at another team, I would play more."