The 1982 World Cup winner is of the opinion that the Argentine's equaliser against the Etnei at the weekend is the reason why the coach is still in charge of the Nerazzurri
The Nerazzurri found themselves in dire straits halfway through the first period after strikes by Alejandro Gomez and Mariano Izco, but managed to fight back after the break to claim a draw.
The former Inter player was highly critical of Claudio Ranieri's side, and stated that the coach would be unemployed now, if not for Milito's late equaliser on Sunday.
"The [Diego] Milito goal saved Ranieri," Collovati told Domenica Sportiva.
"After the first 70 minutes against Catania, Inter would have found it very difficult to keep him [Ranieri].
"He has to start improving. Currently, the only positive is the performance of certain individuals."
Following Sunday's draw, Inter have extended their winless streak in all competitions to nine games and are currently 11 points off the Champions League places in Serie A.