The striker has previously stated that he would leave a match if there are any more instances of racist chanting, such as those in the recent Serie A clash between Roma and Milan. 
However, Allegri does not feel it should have to come down to players to tackle racism and advised Balotelli not to leave the field of play should it occur again. 
"I told Mario Balotelli that I need him to remain onto the pitch and that we need 11 men onto the pitch, because we could have some difficulties with 10," he said. 
"He reacted like that after the match, but he knows very well that those decisions are not up to him, it's up to other people to stop a game when there is racist chanting again. 
"And when they start making different decisions, maybe they will put an end to racist episodes."
Milan face already relegated Siena but Allegri said he was well aware of the threat they could cause to his side.
"(The) game will be very difficult because Siena will try to get a great result in front of their supporters, before leaving Serie A after three or four years," he said. 
"We need to be patient, we need to be open and play with great intensity, aside from trying to play good football. The guys have had a good week, despite the pressure and they're ready to play a great game tomorrow and close the season in the best possible way, because they deserve it."