'Walking Dead' cast reassures fans the show is in good hands As the main characters of "The Walking Dead" question whether Rick Grimes is fit to be in charge in his unstable state, the cast of the AMC ratings force finds itself under new leadership for the third time in its going-on-four-year run. And they want fans to know: It will be OK. The network finally confirmed earlier this week that Glen Mazzara would be stepping down as show runner for the upcoming fourth season, replaced by show writer Scott Gimple. And as the cast and executive producers gathered for a PaleyFest panel Friday night in Beverly Hills, the changing of the guard was obviously a hot topic in the stuffy press tent prior to the event. "To the fans, I say: Worry not," executive producer Greg Nicetero told The Times. We're in fantastic hands. Scott Gimple has written some of the best episodes. He knows the genre and he's a great writer. As far as I'm concerned, it's a match made in heaven. Gimple, who wrote Sunday's Season 3 episode, comes in at an auspicious time for the zombie drama. It recently became the first cable series to win the fall TV ratings in the advertiser-coveted 18-49 demographic. Its return last month brought in 12.3 million viewers. "It's hard when there's a change in the guard," said Laurie Holden, who stars as Andrea. And I understand the concern. But the fans have nothing to worry about; we're a well-oiled machine. Andrew Lincoln, who as Rick Grimes serves as the leader of the survivors, chose not to comment on the boss changes. But Steven Yeun, who plays Glenn, said the renovations are less daunting when the foundation is intact. "We have the core," Yeun said. That's all that matters. We're fine. Glen was great, Scott is great. I'm glad we kept it in-house. OK, sure. But there's no denying the bloodshed behind the scenes is starting to rival the onscreen carnage. Gimple replaces Mazzara, a veteran on "The Shield," who had replaced series creator Frank Darabont. The switch-up came at a time when the series had been riding a wave of highs, though fans of the show had grown frustrated with a drifting second season. The latest shake-up has many wondering if the cable darling's internal drama is overpowering the show. "All I can say is these kinds of things happen all the time on shows," said Robert Kirkman, an executive producer and the creator of the comic book from which the series was adapted. But this frequently, we ask? Well, yeah, in a lot of cases, yes. I think because there is such a huge spotlight on this show, it becomes a bigger thing. You know, Scott's a writer -- he's not only written episodes but he's been an integral part of the writers room since he joined the show in Season 2. Now that's he's coming in and stepping up, it's been a very smooth transition. I'm happy to say, if anything, the show can only get better. Fans will have to wait and see. Production on the new season will begin May 6, with the 16-episode season set to roll out in October. Glen Mazzara out as 'Walking Dead' show runner 'Walking Dead' first cable series to top fall TV ratings Fans join in wife-bashing on 'Walking Dead,' other AMC series