There's been claims this week Juve have offered Ronaldo across Europe, including to Barcelona.
But Cambiasso told Sky Italia: "The risk is that the loss of one of the two best in the squad could be seen as a surrender from the outside.
"The club must be strong, Ronaldo has a great impact when you take him but in the same way he makes news when you eventually sell him.
"I think of my Inter, when (Zlatan) Ibrahimovic left. In situations like this, the club's communication must be strong."