While Avengers: Age of Ultron hasn't even hit theaters yet, the rumors are already starting to fly fast and furious about Avengers 3. Once recent rumor had it that Avengers 3 would be split into two different movies.
Now, BadAssDigest.com offers up a different spin on what might be going on with Avengers 3. While the site claims the whole splitting of Avengers 3 isn’t possible from a legal standpoint, because of the contracts that Marvel Studios has with actors, they do have information that suggests something else is being planned.
According to BadAssDigest.com, Marvel Studios is planning to keep many of the current Avengers out of Avengers 3 altogether in order to save their biggest characters for something else. They specially mention Thor, Captain America, Hulk and Black Widow as characters that might not be in Avengers 3. The site hints Thor and Captain America could be tied up dealing with fallout from their third movies, Hulk might not even be on the same planet by that time, and Black Widow could easily be explained away as being on another adventure.
Robert Downey Jr.’s contract is reportedly specially tied to Avengers 3, so he might well be the only member of the original Avengers movie to make the cut. The rest of the characters surrounding Iron Man could be secondary characters from the Marvel Cinematic Universe, who have to step up to prove their worth.
This would allow Marvel Studios to save some of their big guns (who only have a couple films at most remaining on their contracts) for an event film that might be even bigger than Avengers 3. While the site claims that the possibility of most of the current Avengers not being in Avengers 3 comes from sources, they classify what the next event could be as speculation. Some possibilities the site mentions is an all-franchise crossover called either Marvel's Infinity Gauntlet or Marvel's Secret War.