In an odd twist of news, it appears that Frank Darabont, co-executive producer and driving force behind The Walking Dead, is stepping down from the show, perhaps quitting entirely, just days after appearing on a panel for it at Comic-Con alongside Robert Kirkman.
No public statement has been issued yet, but both Deadline and The Hollywood Reporter are confirming that Darabont has left the show, which is in the middle of filming season two. That doesn't mean that there isn't all kinds of speculation, though, ranging from previous comments that Darabont made about AMC's possibly lower budget on Season 2 to the fact that he might simply not have ever adjusted to the pressures of working on television, which is a much faster-paced environment than movie-making.
He might also have felt that he simply wasn't needed anymore, as he and Kirkman hired a full writing staff for the second season of the show, as well as Glen Mazzara as another executive producer. Mazarra worked on The Shield, and has acted as a showrunner before, so perhaps Darabont simply felt that he'd be a capable steward for his creation and that it was time for him to get back to moviemaking. Still, the fact that he was talking up Season Two just a couple days ago does make this a bit odd, if not suspicious. I'd guesstimate that some kind of official statement will be made today; we'll update this story when we can.