The Walking Dead Renewed for Season 4; Glen Mazzara Steps Down as Showrunner

Expected and shocking news today out of AMC:

The network has renewed cable's biggest hit, The Walking Dead, for a fourth season, but there's a surprising catch: showrunner Glen Mazzara will not be around to oversee it.

“Glen guided the series creatively for Seasons 2 and 3,” AMC said in a statement. “[We're] grateful for his hard work. We are both proud of our shared success. Both parties acknowledge that there is a difference of opinion about where the show should go moving forward, and conclude that it is best to part ways. This decision is amicable and Glen will remain on for post-production on Season 3B as showrunner and executive producer.”

After The Walking Dead Season 3 is over, Mazzara says it will be "time to move on," adding:

"I have told the stories I wanted to tell and connected with our fans on a level that I never imagined. It doesn’t get much better than that. Thank you to everyone who has been a part of this journey.”

This, of course, marks the second creative shake-up on a series that blows away ratings records with each outing. Frank Darabont left after The Walking Dead Season 1 and was replace by Mazzara.

Says creator Robert Kirkman in his own statement:

“I am in full support of both AMC and Glen Mazzara in the decision they have come to and believe the parties came to this decision in the best interest of the future of the show. I thank Glen for his hard work and appreciate his many contributions to The Walking Dead and look forward to working with him as we complete post production on Season 3. I am also excited to begin work on another spectacular season of this show that I know means so much to so many people. This show has always been the result of a wide range of extremely talented men and women working tirelessly to produce their best work collectively. I believe the future is bright for The Walking Dead. Thank you to the fans for your continued support.”

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.