During a virtual Comic-Con@Home panel on Fillion's career, Fillion got Torres to say she would guest-star on his ABC police drama. But she pointed out that when she guested on Castle, "you bailed." The Rookie creator Alexi Hawley assured Torres that she and Fillion would share scenes with him. "There's no way I'd bring you on the show and not write you into Nathan's story," Hawley said. Firefly alum Alan Tudyk, who participated in Fillion's panel, already guest-starred on The Rookie in Season 2.