In the comics, the Avengers has always been a very fluid roster with multiple different characters going in and out of the team on a regular basis. In a way, Avengers membership has sometimes been a joke in the comic as it seemed like every major hero in the Marvel universe had a membership card.
There have been rumors that the events of Age of Ultron would shake up the team, and Kevin Feige confirmed to Buzzfeed that we’ll see that:
â€œItâ€™s like as it was in publishing, when each of the characters would go on their own adventures and then occasionally team up for a big, 12-issue mega-event. Then they would go back into their own comics, and be changed from whatever that event was. I envision the same thing occurring after this movie, because the [Avengers] roster is altered by the finale of this film.â€
One of the rumors is that we’ll see two teams. Cap will form a “West Coast Avengers” style team with Iron Patriot, Black Widow, Hawkeye, Scarlet Witch, and Quicksilver. Tony will take the heavy hitters with him to New York in a team that is made up of Iron Man, Thor, Hulk, and The Vision.
That’s definitely the sort of situation that could set up the superhuman Civil War…