The Italian soccer federation says the striker has "a minor right knee problem." He'll be re-examined by a team doctor on Sunday.
Balotelli has been the target of reported racial abuse in matches against Croatia and Spain during Euro 2012. UEFA opened a case against the Croatian soccer association after reports that fans made monkey chants toward Balotelli.
The injury could open up a spot for Antonio Di Natale in the starting lineup.
Di Natale replaced Balotelli in the second half of Italy's opening two matches, 1-1 draws with Spain and Croatia, and scored against Spain.
Italy needs to beat Ireland in its Group C finale and get help from Spain and Croatia to advance.