According to a report on Deadline.com, Frank Darabont has stepped down as showrunner on the second season of The Walking Dead – which will come as a great surprise to fans of the series who attended Comic-Con last weekend, where the Shawshank Redemption director was enthusing about the new season.

The Deadline report suggests that Darabont “never quite adjusted to the daily grind of producing a TV series” and it is unclear whether he has left the production altogether, or if he will remain in some capacity. The Shield‘s Glen Mazzara was appointed executive producer for the second year as Darabont’s number two, but as yet no formal announcement has been made about his position on the series.

Update: HBO has confirmed that Glen Mazzara will step up as showrunner for the rest of the second season, and that negotiations are ongoing with Frank Darabont regarding his role.