The Manchester City boss has claimed that the Italian striker needs to work harder than he is in training in order to get back into the first-team fold at the Etihad Stadium
The enigmatic frontman was left out of the City squad last week as they ran out 2-1 winners over Tottenham at the Etihad Stadium.
Mancini and Balotelli have had a love-hate relationship in the past, with mixed results. But the Citizens boss has revealed that the Italian was dropped against Spurs because of poor performances in training.
"I told him this was the reason - because he didn't work well for three days," he told reporters.
"I think Mario needs to work harder. If any player doesn't work hard it is difficult that he can play at this level.
"What you do in training you do in the game, and every player needs to work hard to improve his performance in the training sessions. After that he can play well in the game."
The 21-year-old Italy international is yet to score in the league this season, but has scored in the Capital One Cup and netted a vital last-minute penalty against Borussia Dortmund in the Champions League.
With crunch games on the horizon, Balotelli will be expecting minutes on the field, although there has been speculation in recent weeks that the striker could be on his way out of the club.