For at least the second or third time, Marvel Studios president Kevin Feige shoots down notion of a Planet Hulk movie.
Planet Hulk is the Marvel Comics comic book storyline that sees some members of the Avengers trick the Hulk into space, and then send him off to live on an isolated planet away from everyone else. Something goes wrong and the Hulk instead gets sent through a wormhole to the Planet Sakaar, a backwards alien world where the Hulk becomes a Gladiator. As the the planet is so dangerous, the Hulk and Banner can't risk transforming into Banner; so Planet Hulk is completely a Hulk story.
And that is exactly why Marvel will not be doing a Planet Hulk movie, because obviously that would mean no Mark Ruffalo.
IGN caught up with Feige:
I think what's cool about the Planet Hulk story is it's all Hulk. He's a gladiator, he's fighting all these creatures on another world. Yes, some of those creatures show up in [Guardians of the Galaxy], which makes people think, 'Oh, maybe it could exist.' And maybe it could exist, someday. I don't think that's the first place we would go though for the very reason that you stated, which is, if we were ever able to do a standalone Hulk movie, 60 percent of the fun would be seeing Mark Ruffalo leading a Marvel movie -- and that's what we would do if we ever went down that road."
While no Planet Hulk movie looks to be getting made, the article did note that Feige "did not entirely rule out the idea of 'Hulk in space.'"
As Feige mentioned above, the Planet Hulk characters do appear in the Guardians of the Galaxy movie with the Sakaarans. It's previously been said that since Marvel Studios didn't have the right to use the Badoon, they instead used Sakaaran warriors.
Furthermore, the animated Planet Hulk movie did feature Guardians of the Galaxy Easter Eggs.