AMC and Walking Dead comic book writer and producer Robert Kirkman were blamed for Mazzara's ouster and called out by name by showrunners Shawn Ryan (Last Resort) and Kurt Sutter (Sons of Anarchy), neither of whom is involved with Walking Dead but both of whom worked with Mazzara on Ryan's FX series The Shield. Ryan tweeted, "It's a real question now why good showrunners should sell to AMC," and Sutter followed with a tweet declaring that AMC had sent him "a gift basket filled with … broken promises and the marinated tongue used to lick Kirkman's ass."
Several insiders confirm that Kirkman, whose detailed graphic novels form the basis of the series, is "very proprietary," as one puts it. One adds, "I believe Robert wants to maintain a certain amount of his control, and AMC needs Robert for the fan base." But despite the vitriol, some sources involved with Walking Dead say Kirkman was one of several producers on the show who had issues with Mazzara and his vision.
One source says Mazzara's shortcomings in running the series during the most recent third season became "abundantly clear … especially for the second half of the season." This source says production was shut down "several times" because of a lack of material.
