The decision was made by president Massimo Moratti after meeting with the striker a day after he threw his shirt to the ground at the end of their Champions League win over Barcelona.
"Mario Balotelli has left the Appiano Gentile training ground after a meeting with President Massimo Moratti," read the statement on the club website.
"The President's decision was made to avoid tension ahead of the game with Atalanta."
Earlier that evening Balotelli had released his own statement apologising for his behaviour.
"When I stepped on to the field and heard the jeers of the crowd and the shouting from the Coach, I lost my head. I didn't understand anything anymore and took off my shirt just to let out that anger.
"I am sorry that I was unable to control the tension and frustration that has been eating away at me for months.
"I was feeling exasperated and this is one of the most difficult moments of my life. I want to clarify I am not angry with the fans, as they always supported me even when others jeered.
"I would love Inter to win everything for them. While I wear the Inter jersey, I will do everything I can to honour it.
"I am going through one of the most difficult moments of my life and feel exasperated, but it was a mistake to react in that way.
"Now I hope to resolve the problems I have with some teammates and the club with the help of those who care about me and my agent."