Ferdinand, who will be part of the Sky Sports team for the Carabao Cup Final live on Sunday from 3pm, scored 50 goals in 84 appearances for Newcastle between 1995 and 1997, and he believes the club are in strong position to keep hold of Isak.
He told GOAL: "I think that's been part of the problem at St James' Park, they get to a point where they've got really good players and unfortunately they sell them. I don't think that's how these new owners in charge of Newcastle will see things, they'll be doing everything they can in their power to keep him. They need to add to what they've got hold and try to build again. If they lose Isak, they go two or three levels back because where do you find another striker like him?
"What they have to do is convince him this club is going in the right direction and I'm sure they're doing that on a regular basis. Everyone's talking about him every week, this club's interested or that club's interested. That's in some way a compliment to him and the club that he's been able to perform. They signed him on a big contract and he's still got a few years left with them, so they're under no pressure to sell unless he throws his toys out the pram."