In what's become a strange annual tradition, the eve of the Television Critics Association press tour has been marked by a surprise resignation. Two years ago, Ben Silverman bailed on NBC. A year ago, Steve McPherson bolted from ABC. Today, Frank Darabont stepped down as showrunner on AMC's "The Walking Dead."

The story was first reported by Deadline Hollywood's Nellie Andreeva, and a source close to the production confirmed that account to me, which explains that Darabont - who wrote and directed the series pilot episode and wrote or co-wrote three of the other five scripts - had trouble adjusting to the pace of a weekly TV series after spending most of his career making movies.

There were reports at the end of season 1 that Darabont wanted to clean house of the show's entire writing staff, assign episodes to freelancers and do all the rewriting himself. Instead, he went with a traditional writing staff, including bringing on Glen Mazzara (who'd written the fifth episode of the first season, and who has showrunning experience (on Starz's "Crash") as an executive producer and his chief lieutenant. As Deadline reported, it's unclear if Mazzara will now ascend to the top spot or if someone else will come in, and it remains entirely possible that Darabont will remain involved with the show in some capacity - just not in the all-consuming position of showrunner.

Perhaps what's most surprising is simply that Darabont and/or AMC believed he'd be up to that grind. Plenty of top feature writers and directors will be involved with making a series pilot, or a single episode (Darabont directed the pilot for NBC's "Raines," and a late-era episode of "The Shield"), but they don't usually stay. It's a different set of muscles, a far more compressed schedule, and not every person in features has the energy or patience to do it.

Also surprising: that as recently as Friday, Darabont was still attached to the show and happy to appear at its Comic-Con panel (which Fienberg live-blogged). The second season debuts on October 16, so decisions have to be made quickly about who will be running the show, whether this changes any of the creative direction of the season, etc.

As for how this will affect "The Walking Dead" overall, I don't know. On the one hand, Darabont's pilot episode was far and away the best episode of that abbreviated first season. On the other, his name was on some episodes that were much less interesting, and I have no idea how heavy an editorial hand he had on the scripts where he didn't receive a credit. Some showrunners rewrite nearly every word, even if their name isn't on the script; others leave their staffers' drafts alone.

Keep in mind also that the show is more than doubling its episode order this season, from 6 to 13. The abbreviated season (which was the only way AMC could make the Halloween premiere date with the windows in everyone's schedule) was no doubt a big reason for why some of the storytelling seemed rushed, why some characters seemed so broad and others so undermotivated. It's entirely possible that with Darabont or without him, the extra time was going to lead to greater consistency.

Or it could be that Darabont's storytelling sense was actually keeping the show more under control than it otherwise might have seemed with someone else in charge, and things could get very messy, very quickly, with the new season.

I'm a big believer in creative continuity on shows - though at least Robert Kirkman, who writes "The Walking Dead" comic, is still on staff - and at first glance this certainly doesn't seem like great news for season 2. But there are too many unknown variables here to say for sure.

I remember sitting down to interview Darabont at last year's Comic-Con. He seemed so excited by the possibilities of an open-ended zombie narrative, one where the nightmare just kept going and going and going, and seemed like he wanted to be there for as long as he could with it. Instead, he's stepping down (and maybe stepping away altogether) after only six episodes were completed.

Sometimes, TV production, like the Green Mile, can just seem so long.