Leonardo was appointed Nerazzurri boss in December 2010 following the dismissal of Rafael Benitez and led the club to the Coppa Italia and second place in Serie A before stepping down the following summer to link up with Paris Saint-Germain.
However, Materazzi, whose departure coincided with that of Leonardo, has nothing nice to say about his former boss and intimated that he might have played a role in the former AC Milan coach's exit.
“I helped him out a lot, but after he stabbed me in the back two or three times, I uncovered him," the former Italy international stated on his Twitter page.
When asked by one of his followers how he would feel about Leonardo returning to San Siro, Materazzi replied: "Over my dead body! We are very different. I am real, he isn’t ... Besides I love Inter, he doesn’t ... It’s not a small detail, you know.
“I said the exact same things to his face. I never talk about someone behind their back. Never!"
Materazzi, who was capped 41 times by his country, spent ten years at Appiano Gentile after arriving from Perugia in 2001.