The season four finale of Chicago PD featured Bush's character, Det. Erin Lindsay, getting a job offer with the FBI in New York. Bush has been with the show, a spinoff of Chicago Fire, since the start.
Chicago PD executive producer and co-creator Matthew Olmstead also left the show during the recent fourth season.
Deadline reports Bush could still return to wrap up her character's story in season five. Bush has appeared in crossovers with Law & Order: SVU before, should her character actually go to New York could she pop up on SVU? That's just an E! News theory, but you never know.
Chicago PD also stars Jason Beghe as Sgt. Hank Voight, Jesse Lee Soffer as Det. Jay Halstead, Patrick John Flueger as Officer Adam Ruzek, Elias Koteas as Det. Alvin Olinsky, Marina Squerciati as Officer Kim Burgess, LaRoyce Hawkins as Officer Kevin Atwater and Amy Morton as Desk Sgt. Trudy Platt. According to Deadline, the show may add another leading female character after Bush's departure.
The season four finale of Chicago PD had 6.5 million viewers and a 1.3 rating in the coveted 18-49 demographic in terms of same day viewers.
Neither NBC nor Wolf Films had a comment on Bush's departure.
Chicago PD airs Wednesdays on NBC and will return this fall.