Zanetti underwent successful surgery this week, with Ranocchia saying that he and his teammates hope to have their captain back sooner rather than later.
"We're all really sorry because it's a long and painful injury," LegaCalcio.it quotes Ranocchia as saying. "I've been through one myself so I know what it's like.
"We're also sorry because he's our captain, he has been ever since I came here, and he's an example to us all.
"However with the physical and mental strength he's got, I'm sure he'll be back soon."
Inter are currently struggling in seventh place in Serie A.