This is what you call kicking a rumor, and the source, while it's down. Last month, a pretty big rumor dropped from the folks at Latino Review which said that Marvel's Phase 3 plans largely focused on The Hulk. Things would kick off in a big way at the end of The Avengers 2, with the Hulk left stranded in space, setting up a Planet Hulk film, only to have him return in time for The Avengers 3 which would be similar to the World War Hulk storyline. That rumor was soon debunked pretty hard, but now Joss Whedon has put the weight of his boot on it, as well.
While at a press junket for Much Ado About Nothing, Whedon had this to say when IGN asked about the Planet Hulk rumors....
Whedon: "Well, I’m really not supposed to comment on it but no, that’s nonsense."
There are times when filmmakers like to play coy with us, but this isn't one of those times. That's just a flat out denial because the rumor was a load of bunk. Oh well. Moving on. You could always just rent the animated movie.