The young Italy international's club career appears to have stalled this season.
And Allegri warned: "Mario must understand that time flies. Balotelli is a major player, with outstanding technical and physical qualities, he has already achieved a lot in his career. But at 23 years of age, he must understand that time flies."
Asked if he'd like to sign the firebrand, Allegri added: "Speaking now of Balotelli makes no sense, he is with Manchester City."