Studios President of Production Kevin Feige forwarded the following email to HitFix:
"We have made the decision to not bring Ed Norton back to portray the title role of Bruce Banner in the Avengers. Our decision is definitely not one based on monetary factors, but instead rooted in the need for an actor who embodies the creativity and collaborative spirit of our other talented cast members. The Avengers demands players who thrive working as part of an ensemble, as evidenced by Robert, Chris H, Chris E, Sam, Scarlett, and all of our talented casts. We are looking to announce a name actor who fulfills these requirements, and is passionate about the iconic role in the coming weeks."
The Avengers supposedly begins production February 2011 with the Hulk as a character,Robert Downey Jr. (Iron Man), Samuel L. Jackson (Nick Fury), Chris Evans (Captain America), and Chris Hemsworth (Thor) confirmed, and Scarlett Johansson (Black Widow). The film hits theaters May 4, 2012.
Norton's WMA Agent has issued a response stating
"(Feige's) offensive statement ... is a purposefully misleading, inappropriate attempt to paint our client in a negative light. Here are the facts: two months ago, Kevin called me and said he wanted Edward to reprise the role of Bruce Banner in The Avengers. He told me it would be his fantasy to bring Edward on stage with the rest of the cast at ComiCon and make it the event of the convention. When I said that Edward was definitely open to this idea, Kevin was very excited and we agreed that Edward should meet with Joss Whedon to discuss the project. Edward and Joss had a very good meeting at which Edward said he was enthusiastic at the prospect of being a part of the ensemble cast."
"Marvel subsequently made him a financial offer to be in the film and both sides started negotiating in good faith. This past Wednesday, after several weeks of civil, uncontentious discussions, but before we had come to terms on a deal, a representative from Marvel called to say they had decided to go in another direction with the part. This seemed to us to be a financial decision but, whatever the case, it is completely their prerogative ... this is no excuse for Feige's mean spirited, accusatory comments. Counter to what Kevin implies here, Edward was looking forward to the opportunity to work with Joss and the other actors in the Avengers cast, many of whom are personal friends of his."
UPDATE II :
See what Ed Norton has to say
PS : Thanks QBan Knight Dude..