Season 21 marks the first time in NCIS history that no original characters appear. This streak ended with the passing of David McCallum, reflecting Ducky’s fate. It’s noteworthy that Sean Murray’s Timothy McGee and Brian Dietzen’s Jimmy Palmer, though long-standing members of the cast, were not among the original characters. Both debuted in Season 1 but were introduced later in the season and initially played recurring roles.
Currently, only Dr. Mallard and Sasha Alexander’s Caitlin Todd, who met her demise in the Season 2 finale at the hands of Ziva David’s half-brother, are unable to return to the police procedural. However, all other original cast members have the potential to make a comeback at any time. While Mark Harmon’s return seems likely, Abby remains the sole original cast member who has not returned since leaving her position. Even if Gibbs does not return to the main NCIS series, his character will be explored in NCIS: Origins, focusing on his early days with Mike Franks’ squad of detectives at Camp Pendleton.
Reintroducing Abby into the NCIS storyline should be relatively straightforward. Given her expertise, any team within the NCIS universe would value her assistance. It would be particularly satisfying to see Abby back in her former lab at the agency’s headquarters in Washington, DC. Ultimately, whether Abby returns to the show will depend on the decision of CBS and Pauley Perrette, the actress who portrayed her.