Treyarch co-studio head and Zombies mode director Jason Blundell has left the studio, the company announced on Twitter today.

Blundell worked on all four of the Black Ops games. He started as an executive producer for Black Ops, became a campaign design director for Black Ops II, and later became the director of the Zombies mode for both Black Ops III and Black Ops 4. Blundell became a co-studio head of Treyarch in November 2016 along with Dan Bunting and Mark Gordon.

We wish to thank Jason for his many contributions to Treyarch. We’ve enjoyed our journey together and wish him the very best going forward! pic.twitter.com/Tb8o36VWb2 — Treyarch Studios (@Treyarch) February 28, 2020

“After thirteen fantastic, action-packed years, I am moving on from Treyarch,” Blundell said. “During my time at the studio, I’ve been privileged to work on a variety of projects, wearing many hats along the way, with my time on the Zombies team proving to be quite special. It’s a team comprised of some of the most creative and talented developers in the industry, many of whom you never see because they’re behind the scenes shaping the direction of each experience.”

No reason was given for Blundell’s departure. He also didn’t mention what’s up next for him in his future. It’s unclear if Blundell left the team or was let go, but it seems to be an amicable separation.

It’s still unknown which development team is working on Call of Duty 2020, but many believe it to be Treyarch, so him leaving the team could have an immediate impact on the game coming out later this year.

What Blundell’s departure means for the future of the Zombies mode in a possible new Treyarch CoD is also up in the air.