Why? Well, because he keeps posting shit like this on Facebook:
Of course, he could just be campaigning for a part in the movie. Or he could be trolling fans again — remember how hard he hinted he would be playing the Vision in Avengers: Age of Ultron?
But let me put forth another theory: I say he's already been cast as Black Bolt, the king of the Inhumans. It's been rumored before, plus there's this benefit — Black Bolt almost never speaks, because his voice is so powerful he can level a mountain by speaking a single word. Could there be a better character than an essentially silent one for Diesel, who's already the voice of the fan-favorite Guardians of the Galaxy character Groot? I think not. This way the actor can be seen and heard in the Marvel cinematic universe, just in two different franchises.
Of course, the Inhumans movie isn't due until late 2018, so there's plenty of time for people to change their minds or things to get messed up before then. But it sure seems like as long as Diesel stays on Marvel's good side, the role is his to lose.
[Via Gamma Squad]