Milan wore anti-racism shirts before kick-off, as Boateng walked off in protest at abuse from the stands during a midweek friendly with Pro Patria.
"There need to be rules set in place to put responsibility on to the fans and clubs," said Allegri.
"Will Boateng leave Milan? No, I doubt it. Didier Drogba will not arrive either, as our policy is to lower the wage bill further."