"Oh, we'll miss her. I'm really aware, and we're all aware that audiences grow to love characters, and it's a big deal. And we honor that," Harmon said. "Fifteen years is a long time. People do what they do, and they move on and they do other things and that's part of life."
He also teased that the show will shake things up after the exit, which is set to happen at the end of the current season.
"It's given us, as a show, an opportunity to rebirth, to rejuvenate, to try new things, to grow," he added. "We adjust."
Harmon's comments echo statements from executive producers George Schenck and Frank Carde, who said there would be a "special send-off" for the actress.
"We've known for some time this would be Pauley's final season on NCIS and have been working toward a special send-off," Schenck and Cardea said in a joint statement. "From day one, she has brought incredible passion and specificity to the role. Abby is a character that inspires millions of fans around the world, and all of us at NCIS are appreciative of Pauley for portraying her."
NCIS airs Tuesdays at 8 p.m. EST on CBS.
Photo Credit: CBS / Sonja Flemming