Spoiler warning, Oct. 16 -- This article discusses the Grey's Anatomy Season 23 premiere.

Jo Wilson's resignation from Grey Sloan will have consequences beyond a single episode, Grey's Anatomy showrunner Meg Marinis says, as the medical drama opens its 23rd season with a new chief of surgery, a pregnancy mystery and a fight over who the hospital should serve.

Speaking to Deadline after the premiere, Marinis said Jo's decision was a creative choice rooted in what the character has experienced-not a move to accommodate a reduced episode count for Camilla Luddington.

Jo tells Link that she has quit after a patient's medical crisis brings back memories of her own near-death experience. Marinis said the story would explore the impact of not...