Earlier this year, it was revealed Harmon had signed a contract for series 19 but only for a handful of episodes.
At the time, it was believed the veteran was scaling back his time in the show in preparation for his departure.
When Gibbs was suspended for the assault in series 18, this was the start of the agent taking a backseat.
Sadly for NCIS fans, Great Wide Open really was Harmon's exit episode.
Source : https://www.express.co.uk/showbiz/tv-radio/1509854/NCIS-exit-Mark-Harmon-permanent184