Nate Getz always wanted to move beyond his analyst role and become a field agent—even though his teammates questioned whether he was suited for the job. Determined to prove himself, he trained in field operations and close-quarters combat, a transition highlighted in Season 2.
Eventually, Nate was assigned to a top-secret mission in the Middle East. This storyline explained his departure from the main team and shifted his presence on NCIS: Los Angeles from series regular to occasional guest star.
While actor Peter Cambor has never publicly commented on why his role was reduced, the change likely gave him the flexibility to pursue other acting opportunities outside the show.