Fans of the comics know that Joss Whedon's upcoming The Avengers features the core members of the team, but it's still missing a few key players. In addition to Iron Man, Hulk, Thor, Captain America, Hawkeye and Black Widow, key members of the superhero group that won't be featured in the movie include Ant-Man, Wasp, Scarlet Witch, Quicksilver and others. While movie rights may prevent characters like Spider-Man or Wolverine from ever joining the Avengers, that doesn't mean that others still under the Marvel Studios banner won't have their shot in the future.

IGN caught up with Marvel Studios head Kevin Feige this weekend at the New York Comic Con and when asked if the second Avengers movie comes around we might see some changes in the line-up. "Absolutely," Feige said. "That's the fun of it -- introducing new characters." The studio is already looking far beyond its plans for next year. Iron Man 3 and Thor 2 are both scheduled to be released in 2013 and projects such as Ant-Man, Captain America 2 and Dr. Strange are currently in various stages of development. What will greatly affect how the next Avengers movie works will heavily depend on what happens in those sequels and solo movies.

"Seeing how will things change after Iron Man goes through his next adventure? After Thor goes through his next adventure? If we do another Cap adventure, how will things change? The dynamic between them? Their own worlds?" Feige said. "So that the dynamic in Avengers 2 is actually quite different than it is in the first one."

What I imagine will likely happen is that some of the characters will be swapped out in favor of some newer characters to keep it fresh. The question is how do you choose which ones to replace? Hopefully it's more of a story thing and less of a box office receipts thing.