The Brazilian midfielder had been linked with a move away from Eastlands for a long time before signing with Galatasaray last week and believes Hughes did not use him properly, forcing him out.
"I'm very, very sad to be leaving Manchester City,” the 28-year old said.
"I loved the club and I loved England. I'm sad to leave all the friends I made and the fans.
"I wanted to stay but circumstances forced me out. I wasn't used properly by the manager.
"People within the club know what happened to me because I'd had very, very good times there.
"The manager has built a team the way he likes and, because of this, I expect him to win the Premier League this season."