That is the opinion of Red Bull chief Helmut Marko, who worked with Vettel during his four title-winning campaigns.
Ferrari came into the new F1 season with plenty of optimism having enjoyed a strong stint testing in Barcelona.
They have, though, failed to build on that promise and trail Mercedes, who have secured three successive one-twos.
Leclerc’s form for Ferrari has been one of few bright spots and it has raised questions over Sebastian Vettel’s future.
Plenty of F1 fans want to see Charles Leclerc given the chance to lead Ferrari and take the fight to their rivals.
However, for now at least, Vettel remains the No 1 driver for the Prancing Horse and will continue to be prioritised in team orders.
Marko, who remains close to former Red Bull driver Vettel, has now weighed in on the debate.
And he has claimed Ferrari team principal Mattia Binotto must bide his time before picking Leclerc over his four-time champion team-mate.
“Let’s wait and see,” Marko told German outlet Bild.
“It’s still very early in the season.”
Leclerc and Vettel will be eager to end Mercedes’ early season dominance when F1 returns to Azerbaijan this weekend.
But former Benetton and Renault team boss Flavio Briatore cannot see Ferrari enjoying a successful year.
“Nothing has changed compared to last year,” Briatore said, when asked about Ferrari’s lack of speed.
“They have not reduced the gap to Mercedes.
“The usual repertoire of excuses already started in the first race.
“Mercedes will continue to dominate.”