"He is a great player, and when he is not there Roma lose a great resource," Leonardo told the press.
"The confrontation between Inter and Roma is now a tradition and the recent past has been very important.
"It will be a great game and, as always, very intense. It is a game that can offer us important signals."
The Nerazzurri were hit by the four-match ban of Cristian Chivu after he punched Bari's Marco Rossi on Thursday.
"We have spoken with Chivu. He is an extraordinary guy and the first to recognize he made a mistake.
"He was rightly banned and the discourse is now closed. It is part of the past now."