Mancini and Balotelli in training ground tiff
Italian striker Balotelli provoked Mancini when he mistimed a tackle on midfielder Scott Sinclair and the pair tussled as coaches tried to separate them.
Balotelli, 22, left the training session hastily before driving away from the Carrington complex.
Balotelli last month accepted a club fine of £340,000 for misdemeanours on and off the pitch and Mancini said he was ready to give him another chance.
However, the latest transgression may prove a step too far for a clearly exasperated Roberto Mancini, who may well use the January transfer window to bolster his attacking options – and perhaps get rid of an ongoing problem in Balotelli.