According to a wrestling website called PW Mania, Dave Bautista is currently in the process of restructuring his contract with Marvel to allow him to get more money due to the huge success of Guardians of the Galaxy. In the process they specifically mention that the actor is slated to appear as Drax in Guardians of the Galaxy 2, and that he will also have a "significant" role in The Avengers 3.

Bautista is a perfect fit for the character Drax, and he seriously disappeared in the role. He brought some hilarious humor and emotional heart to the character, and I think it surprised a lot of people.

I've been speculating for some time that the third Avengers film would include a team-up with the Guardians of the Galaxy. So if Drax will be in the movie, it's only safe to assume the rest of the team will be in it as well. There's no official confirmation of this, but it makes sense that these two superhero groups would come together and battle big bad Thanos.

The Avengers 3 hasn't been officially announced yet, but common… we know it's going to happen. I think it's safe to say that it will be the capstone of the Marvel Cinematic Universe's Phase Three.

I believe that Avengers 3 will follow the Infinity Gauntlet storyline from Marvel Comics. It features several superheroes from around the galaxy coming together to defeat the Mad Titan Thanos, who has used the Infinity Stones to basically become a god. Drax plays a very very important role in this storyline, so I got pretty excited when the site said he would have a "significant" role in the movie. That tells me this very well could be the story Marvel will move forward with.

SPOILERS Ahead for those who haven't read the comics:

This could also implement a story arc called "Annihilation" in which Drax actually ends up killing Thanos. Killing Thanos is one of the main reasons that Drax even exists. It's definitely in Marvel's best interest to keep Bautista around because the fans love him.

Again, this is all just a rumor since there has been no confirmation, but it makes complete sense to me that this is how it could play out. Avengers 3 will be released sometime in 2018.