While rumors like this are always best to take with a grain of salt, the idea behind it is still interesting. If it's true, who could Vin Diesel be playing?
Obviously, we can rule out any roles that we already know are cast (such as Crossbones in Captain America: The Winter Soldier or Malekith in Thor: The Dark World). We can also rule out any roles the he COMPLETELY wouldn't fit in (ie, Dr. Pym, Wasp, Ms. Marvel.....my God do I hope we can rule those out).
What possible roles does that leave? Here is a breakdown of some potential options as I see it:
1. Groot in Guardians of the Galaxy
One of the rumors going along with this is that he'll be doing voiceover work as opposed to acting on screen. This makes the most sense out of anything, to me. I don't know too much about the Guardians of the Galaxy series, but just by looking at Groot, couldn't you imagine him having Vin Diesel's voice?
2. Rocket Raccoon in Guardians of the Galaxy
Less likely, but who knows...maybe Marvel wants to take this ridiculous character and make it even more ridiculous by giving it a voice that completely doesn't match the concept.
3. Vision in Avengers 2 (or Ant Man)
While I'd like to see Vision appear, I'm hoping Vision doesn't show up until they can do Ultron right and I don't think Ultron is the best fit for the first Ant Man film. The sequel, on the other hand, or the third film in a trilogy, would work better. With the inclusion of Scarlet Witch in the Avengers sequel (ugh...don't get me started on how I don't like that idea), there's a chance Vision DOES show up, considering their relationship. Vin Diesel is pretty robotic in his voice...that could fit. Plus, he could provide the motion capture for the role as he looks somewhat similar to the build that Vision has.
4. Thanos in Guardians of the Galaxy / Avengers 2
He's big, muscular, he has a deep and intimidating voice, and he's a rather well known actor. I'm much more into the rumors that Benicio Del Toro is instead playing Thanos, but that's looking a bit less and less likely as time goes on.
5. Some Random Other Character (in ???)
As we've seen many times in the other films, just because someone is cast doesn't mean that they're going to play someone from the comics. Dr. Selvig is a perfect example. Vin Diesel could just as easily be playing someone brand new created for a film that none of us would be able guess, since he'd simply be a random person. To be fair, though, Marvel has a much better track record than DC when it comes to using characters from the comics in cameos. Doc Samson found his way in the Incredible Hulk movie, as did many others, while Man of Steel and the Dark Knight trilogy almost on purpose tend to use characters similar to a comic book one, while giving them a new name. Okay, okay, I digress in my rant, I'm sorry. The point here is that Vin Diesel, even if he's legitimately going to play SOME part in an upcoming Marvel film, doesn't have to be playing someone from any comic that we've seen before.
Who do you think Vin Diesel will be playing—or do you think this is total bullshit and he won't be involved in any way whatsoever?