Anyone else remember back in the Spider-man 2 days when Lindsay Lohan was 'cast' as Gwen Stacy, according to IMDB? The entry was made by a fanboy with an IMDB account. Recently IMDB's Batman 3 page has seen a lot of fake 'rumored' casting of no-name actors in big name roles. Ultimately it was determined that the F-listers themselves had made the entries simply to make their IMDB popularity go up 2000%. Now in the case of Captain America, there were times where you could visit IMDB's Cap page and see that John Krasinski, Chris Evans, and Mike Angel were all playing Steve Rogers against Kiera Knightley, Jackie Earl Haley and Lou Ferrigno.
In short, I don't buy anything I read on IMDB until there's a Marvel press release to prove it.