The Sunday Mirror says Balotelli was left out of the City squad for Âyesterdayâ€™s trip north to Newcastle.
Mancini made clear his anger, amid claims that the playerâ€™s training had not been up to standard in the past few days.
Questioned on why ÂBalotelli didnâ€™t travel to the north east, Mancini Âreplied: â€śMario is not in good form at the moment.
â€śIt is better for him to train well.
â€śHis form is not good enough to play.â€ť
Privately, the City boss now wonders whether ÂBalotelli will ever fulfil his potential.