Several British newspapers published pictures on their websites of Mancini shouting at the Italy striker and appearing to grapple with him and of the two men being separated.
It is reported Mancini stepped in after Balotelli went in too strongly for the City manager's liking on teammate Scott Sinclair.
Balotelli is reported to have taken exception to Mancini's intervention, leading to the pair having to be pulled apart.
In the sequence of pictures that were published, Mancini is seen striding towards the 22 year old, pointing in an aggressive manner.
He is then seen to grab hold of Balotelli's orange bib before the young striker is dragged away by a member of City's coaching staff.
A short time later, Balotelli is believed to have left the training ground at Carrington.
Balotelli has not played for City since the Manchester derby on December 9 having been ill for much of the Christmas period.
Meanwhile, Mancini has until this afternoon to offer his observations about his comments regarding the referee Kevin Friend following City's defeat at Sunderland on Boxing Day.
The English Football Association wrote to Mancini following his claim that "maybe the referee ate too much for Christmas" after Friend missed what the City manager felt was a clear foul on Pablo Zabaleta in the build-up to Adam Johnson's winner.
Although over a week has now passed since the incident, the judicial panel granted Mancini's request for an extension because of the demands placed upon him during the packed festive period.
It is thought Mancini is facing either a warning or a fine for his reaction, although the disciplinary panel do have the option of a touchline ban should they wish.