Leonardo left last summer to become a director at PSG.
Materazzi snapped: "As an Interista, I am disappointed by this season, as they could've done more, but it could've ended worse too. Now they have all the time needed to begin again from Andrea Stramaccioni.
"Last year our ex-Coach Leonardo abandoned us just five days before pre-season training began. He said that he didn't feel up to it, but that was a terrible thing to do and Inter really suffered for it.
"The thing that upsets me is there is talk of his return. Leonardo contributed a great deal to the current problems. Abandoning the ship a few days before setting off is not the work of a good captain.
"Who do I prefer between Zinedine Zidane and Leonardo? I choose the Frenchman, who carried on his ideas without looking back, whereas Leonardo was not consistent with me."