AMC's zombie drama shut down production "several times" because of the scripting crisis, according to The Hollywood Reporter.
The article also suggests that The Walking Dead comic book writer Robert Kirkman was "very protective" of his work and clashed with Mazzara.
The Walking Dead was picked up for a fourth season in December, minus Mazzara's involvement - his firing came less than 18 months after original showrunner Frank Darabont was also let go from the series.
Responding to The Hollywood Reporter's claims, Sons of Anarchy creator Kurt Sutter - who worked with Mazzara as part of the writing team on FX drama The Shield - wrote on his WhoSay page: "[Glen] didn't run low on material. he's finding the right mix for an effective show. and that's very difficult to do when RK [Robert Kirkman] strangleholds the mythology."
He continued: "Ratings and fan approval cannot be denied. The show is / was infinitely better because of [Mazzara's] talent."
Sutter previously criticised AMC when news of Mazzara's firing first broke, claiming that the cable network is "run by small-minded, bottom-line thinkers who have no appreciation or gratitude".
"Mazzara took the work-in-progress that was Walking Dead and turned it into a viable TV show with a future," he wrote. "Without him, that future is dim."
The Walking Dead's third season resumes on February 10 on AMC. The series airs on FX UK - to be rebranded Fox from January 11 - in the UK.
> The Walking Dead was turned down by NBC: "It was an early draft"
Watch a promo for the return of The Walking Dead below: