Balotelli angered fans at the end of Inter's victory over Barcelona by throwing his shirt to the ground.
Moratti said: “Now it's difficult to mend.
“It's not impossible, but something will have to give… It's as if Balotelli committed suicide in public. But I have faith in him and I don't intend to sell him.
“I don't know if he'll play against Atalanta. There is a lot to do. We'll see.”