Cassano left the San Siro last summer after just one season with Inter, signing for Parma after Mazzarri decided that the forward did not feature in his plans.
The 31-year-old believes that Inter are capable of earning Champions League qualification this season, but does not care for Mazzarri on a personal level.
He told Tiki Taka: "The championship will for me be won by Juventus and in the Champions League places will be Napoli and Inter.
"Inter have a top coach, but as a person he is less great. I'm convinced, however, that he will do great things.
"I am rooting as an Inter fan and for Inter, but not for Mazzarri, I do not give a damn about him, I am interested in what Inter achieve."
Cassano has shown flashes of a return to form with Parma this season, scoring twice in seven appearances for Roberto Donadoni's side.