Regardless, even ignoring Mark Harmon’s potentially reduced screen time, NCIS will look quite different in Season 19.
Maria Bello departed as Jack Sloane in the Season 18 episode “True Believer,” but that exit was at least announced ahead of time.
Then Emily Wickersham departed as Ellie Bishop in “Rule 91,” as after being willingly being disgraced as an NCIS agent, Ellie turned in her badge and embarked on a long-term, undercover operation afterwards.
Besides Gary Cole, no other new faces being looked at for NCIS Season 19 have been revealed yet, but was previously reported that Katrina Law’s Jessica Knight, who we met in Season 18’s final two episodes, has the potential to become a series regular.