CBS All Access' Star Trek: Discovery is making its second showrunner change.

Out are Gretchen Berg and Aaron Harberts, who originally took over the role at the helm of the drama from Bryan Fuller. Executive producer Alex Kurtzman, who has guided the franchise (and a few of its feature films), will take over as showrunner on season two. As part of the change, Kurtzman will now also oversee the Discovery writers room for season two.

"We’ve made some producer changes at Star Trek: Discovery. The series continues under the creative vision and leadership of executive producer and co-creator Alex Kurtzman. Discovery remains on course for season two in 2019 with new and continuing stories that build on its successful premiere season," producers CBS Television Studios said Thursday in a statement to The Hollywood Reporter.

Sources say the decision to oust Berg and Harberts was based not on the creative but instead for leadership and operational issues. Production on Discovery's first five episodes of season two are near completion, with Kurtzman likely taking over for episode six and beyond. Berg and Harberts, who were longtime collaborators with original showrunner Fuller, will likely still be credited on the episodes they oversaw. Sources say the budget for the season two premiere ballooned, with the overages expected to come out of subsequent episodes from Discovery's sophomore run. Insiders also stress that Berg and Harberts became increasingly abusive to the Discovery writing staff, with Harberts said to have leaned across the writers room table while shouting an expletive at a member of the show's staff. Multiple writers are said to have been uncomfortable working on the series and had threatened to file a complaint with human resources or quit the series altogether before informing Kurtzman of the issues surrounding Berg and Harberts. After hearing rumors of HR complaints, Harberts is said to have made imposing remarks to the staff to keep concerns with the production an internal matter.

Sources tell THR that Discovery is nearing what has been characterized as a planned production hiatus after episode five, which will allow Kurtzman time to regroup the show's writing staff. Production is not expected to be impacted by the showrunner change.

In another departure for season two of Star Trek, THR has learned that executive producer Akiva Goldsman did not return to Discovery after serving as Kurtzman's right-hand man during its freshman run. Goldsman was brought in to help build the world of Discovery, but the veteran producer, who directed the season one finale, is said to have had a management style and personality that clashed with the writing staff. It's unclear if Goldsman will continue to receive an exec producer credit on season two.

This is the second showrunner change on Star Trek: Discovery. Former showrunner Fuller clashed with CBS over the show's concept, casting, directors, costumes and budget on top of its original launch date. (The series was originally slated to premiere in January 2017 and was delayed twice.)

In October 2016, Fuller was asked to step down as showrunner — after growing up as a diehard fan of the franchise and eventually working on Deep Space Nine and Voyager — when the network grew frustrated that he was splitting time with Starz's hyper-stylized American Gods adaptation. Fuller's longtime collaborators, Berg and Harberts, were tapped to replace him. (Fuller and co-showrunner Michael Green were subsequently fired from American Gods after clashing with producers FremantleMedia over that show's budget.)

Amid all the changes, Kurtzman — who directed the series premiere — has been the glue holding Discovery together. CBS and producers CBS Television Studios are said to be pleased with the cuts and scripts they have seen from season two. Discovery is expected to return in 2019, when it will lean deeper into the Star Trek mythology with the casting of Anson Mount as Captain James T. Kirk's predecessor, Capt. Christopher Pike.