After Barcelona testing, while many believe Mercedes has its nose in front, the conventional wisdom is that Red Bull and Ferrari could make it a close fight.
Massa told Corriere della Sera: "That would be nice. But I fear it will not happen.
"Many things are said in the pre-season and then the races are different. And for now Mercedes has not shown anything.
"So when you're Mercedes and you win so much, you cannot fail to be the favourite. You can also see from [Lewis] Hamilton and [Valtteri] Bottas's faces that they are more than satisfied.
"A driver is not able to hide that well."
Massa therefore thinks that while Ferrari has improved in the last few years, the Italian team is "still missing something" in order to be the favourite.
Mercedes beat Ferrari to the 2017 constructors' championship title by 146 points.