The 40-year-old claims that "everything needs changing" at the Italian club including coach Andrea Stramaccioni.
"Everything needs changing," he told Sky Sport Italia. "The coach is confused and the squad is not good enough.
"If Inter change, then they need to hire a coach who will also be able to supply them with a shopping list. They need players who will allow them to take a step up in quality. Important players are required."
Inter are currently seventh in Serie A with 50 points from 32 matches.