Well, Edward Norton and Terence Howard have to be kicking at clumps of dirt and cursing quietly this week.
Those two may have been forced out of roles they wanted to keep in the Marvel Cinematic Universe, but after Hugo Weaving confessed earlier this week to having no interest in returning to reprise the role of the Red Skull, TG Daily (via CBM) is now reporting that Thor star Natalie Portman is only back as Jane Foster because Marvel declined to let her out of her contract when she said she didn't want to be there.
"It’s not something I would want to do again," Weaving said in an interview earlier this week. "I’m glad I did it. I did sign up for a number of pictures and I suppose, contractually, I would be obliged to, if they forced me to, but they wouldn’t want to force someone to do it, if they didn’t want to."
And then, TG Daily points out, "Ironically, we recently learned that Natalie Portman is being 'forced' into her contractual role as the romantic lead in Thor 2, another Marvel Film Universe sequel, despite a desire to back out."
That's all--no reason is given as to why Portman would want to back out, nor is there any solid evidence that she hoped not to come back for the sequel outside of the site's claims.
Portman was, however, reportedly on the side of Patty Jenkins, the Monster director who was originally tagged to take on Thor: The Dark World and then upset when Jenkins was abruptly dropped from the project. Jenkins, who would have been the first female director to tackle a Marvel Studios movie (or, indeed, a major tentpole superhero film of any kind, although as pointed out in the comments below, Lexi Alexander directed Punisher War Zone, a Lionsgate film that featured a Marvel character), was fired in favor of Alan Taylor, whose resume includes genre hits like Game of Thrones and Lost.
While Weaving's observations had nothing to do with Marvel as a studio and essentially boiled down to "That sort of movie isn't for me," the notoriously-stingy Marvel Studios has had it out with actors and directors over money more or less since the Marvel Cinematic Universe began--and now that the films are making record sums of money and signing on for these pictures is such a feather in the cap of almost any actor, it's probably more likely that Marvel has leverage over all but the biggest-name stars, rather than any scenario that would see them adapting and offering their creative types more money.
Portman's performance in Thor has drawn a lot of jeers from fans, something that will no doubt color the commentary on her desire to walk away (a quick look at CBM's comment thread confirms this suspicion), but that doesn't change the fact that she's still geek royalty, having starred not only in the Star Wars prequels but in the fan-favorite film adaptation of Alan Moore and David Lloyd's V for Vendetta.
Regardless of the circumstances surrounding her return, it seems unlikely Portman will have to spend a ton of time on set; Thor: The Dark World explores all nine realms and deal with Thor battling Asgardian politics, Malekith and the Dark Elves and possibly Loki, who will appear in the film and whose story will deal with the aftermath of his role in this summer's The Avengers. While Portman, Thor's earthbound love interest, will return alongside her sidekick Kat Dennings, it seems unlikely the movie will spend a lot of time on Earth.