Boyata has joined FC Twente on-loan this season.
"In August I requested a transfer to FC Twente," he told Voetbal International.
"City had nine defenders in their squad. Only four of them can play and only two can sit on the bench. Even in the stands there were bigger names than me.
"I wanted to fight for my place as I am not someone to run away from a challenge. However, sometimes you have to stop dreaming, be realistic and leave.