Isak started for Newcastle against Wolves on Sunday and scored in a 2-1 win for the home side at St. James’ Park.
Wilson has been preferred by Eddie Howe as the starting striker and despite his lack of goals, the Newcastle boss has backed him to make an impact this season.
However, Cascarino insisted that it is time Newcastle replace the veteran forward with Isak up front in most games.
He believes the Swede has settled well in the Premier League and can do more up front for Newcastle than Wilson.
The former top flight star feels Isak’s dynamism, pace and ability to hold the ball will help Newcastle to play more on the front foot and allow their creative players to push more forward.
Cascarino wrote in his column for the Times: “I’ve always been a fan of Callum Wilson but Alexander Isak looks ready to replace him as Newcastle’s leading man.
“The Swedish striker has settled well in the Premier League and is a little more dynamic than Wilson — helped of course by being eight years younger than him.
“What I like about Isak is that, as well as having good control and hold-up play, he runs in behind and stretches defences.
“That helps Newcastle to extend teams and force the opposition defence back towards their goal.
“That then helps Newcastle move their creative midfielders and Kieran Trippier higher up the pitch where they can be a threat.
“With the financial backing they have I’m sure Newcastle will spend big in the summer but they might already have their next No 9.”
Newcastle paid a club-record fee to sign Isak last summer but his first season at the club has been marred by injuries so far.