FX is still moving forward with its series adaptation of the beloved comic book series Y: The Last Man — but not with the original showrunners. Aida Croal and Michael Green on Monday announced their exit in a statement on Twitter.

The Hollywood Reporter has confirmed that the project is still a go at the network, with the same cast in place, but the hunt is now on to replace the duo who had shepherded the development and piloting of the series now just being dubbed Y. Sources say that the exit came after creative differences with the network over the course of the show.

Ordered to series earlier this year, Y is not the first attempt to adapt the comic series for live action, as there was a long-gestating film project that went nowhere. But after Croal and Green brought their pitch to the network, and Diane Lane and Barry Keoghan starred in the pilot, FX boss John Landgraf seemed particularly bullish about the project when he formalized the series order at a February meeting with reporters. Nina Jacobson and Brad Simpson of Color Force serve as executive producers, alongside source material author Brian K. Vaughan and pilot director Melina Matsoukas.

Y: The Last Man ranks as one of the most critically acclaimed comic book series of the 21st century. The DC Comics/Vertigo effort — which was launched in 2002 and was written and created by Vaughan and artist Pia Guerra — ran for 60 issues and has since been collected in a series of graphic novels.

This is the second big TV project that Green has departed in recent years, having left Starz's troubled American Gods adaptation alongside Bryan Fuller after the first season. That said, showrunner departures have become more and more commonplace against the backdrop of TV's substantial uptick in scripted programming.

FX put the Y adaptation in development in late 2015 after Vaughan reacquired the rights to his franchise after they'd been tied up by New Line, which ultimately failed to get an effort on the screen. Vaughan told THR in November 2017 that he "wanted to find someone who loved the source material but didn't feel so indebted to it that they would be afraid to change it," with Green fitting that bill. "When [Green] first pitched his take on it to Nina Jacobson and me a long time ago, he came in saying he wanted to do something about toxic masculinity. It felt very relevant, and unfortunately, I think it's only become more relevant with each passing day. His take on it was really brave and very different, but exciting as well. I really admire how audacious he's been with his translation."

Alongside Keoghan and Lane, the series also stars Amber Tamblyn, Imogen Poots, Lashana Lynch, Juliana Canfield and Marin Ireland.