Livorno striker Francesco Tavano was confronted by ultras at training on Thursday.
It's alleged Livorno fans invaded the training pitch and one slapped Tavano.
Police intervened to calm the situation, but the fans went back to the stands and continued to chant insulting comments at the squad.
They took particular aim at Tavano, Mozart, Davide Marchini and goalkeeper Alfonso De Lucia.
Livorno president Aldo Spinelli has already declared he is putting the club up for sale this week.