Pazzini scored in the 2-0 victory at Genoa on Friday night, but limped off with a heavy knock to his shin and there were even fears of a micro fracture.
"The game turned into a battle and we did well to fight back blow by blow without thinking about Tuesday," Tassotti told Milan Channel.
"If Pazzini isn't fit, then it would be a problem. He was in great shape and scoring important goals. There are other players, but it's better to have everyone at your disposal to make the best choice."