The Italian bad boy, 20, signed a five-year deal worth around £4m a season at Eastlands but then revealed on his personal website: "I am sad to leave Inter Milan because I'd have preferred to carry on professionally in my home country.
"But I'm about to begin a new adventure. I'm going where I hope I will find the space to play because, for me, that is very important.
"I need to play, to make mistakes, to learn and to play even more. I also need a more serene atmosphere."
Balotelli had a mixed last year at Inter, during which he regularly fell out with boss Jose Mourinho while his team went on to win the Champions League.
He added: "I leave behind a difficult year.
"I've recognised my mistakes but believe I have found myself at the centre of pressure and criticism which, in certain cases, left me exasperated.
"Now all I am thinking about is playing well for my new team in the Premier League and I will give it my best effort."