Fans were thrown for a loop when Vin Diesel was cast to voice Guardians of the Galaxy's Groot, as he was heavily rumored for another major role in the Marvel Cinematic Universe. In a new interview with io9, the Fast & Furious actor said it's not out of the question and he hints at who it might be.
“I can totally be something [else] with Marvel,” Diesel said. “I think playing [Groot] only makes Marvel that much more excited and me having my experience with Marvel, seeing how great they were, makes me more excited. We’ve heard a lot of talk about Marvel wanting to have me play a character that doesn’t have my voice. So my voice is used for Groot and my presence is used for the other character."
Thor: The Dark World actor Zachary Levi previously revealed that Marvel Studios President Kevin Feige said that an actor could pull double-duty in movies
So if Diesel's voice is identifiable as Groot in the MCU, he could still play another role if there was a character who didn't speak -- or had some type of modified voice.
There's a number of characters in the Marvel Comics library that don't speak or speak very little. There's villains such as Psionex's Asylum and even previous movie stars such as Man-Thing. There's even a 1970s Jungle Action character named Mute.
But chief among all would be Black Bolt. With that character being synonymous with the Inhumans, there's a movie planned and a major storyline running through the Agents of S.H.I.E.L.D. television series.