NEW YORK >> The lead character of television’s most popular drama exited the show Monday without a fuss, and without the immediate ratings bump that would be expected if there had been.

“NCIS” star Mark Harmon, who has played Special Agent Leroy Jethro Gibbs since the CBS drama began in 2003, had his final night as a regular character on Monday’s show. Gibbs informed his partner after working on a case in Alaska that he was going to stay there.

At Harmon’s request, CBS made no special promotion of the occasion, a muted departure for an industry that has never been shy about hawking the movements of big stars.

That may partly be because Harmon, 70, hasn’t ruled out the possibility of an occasional return.

“Our north star has always been staying true to our characters, and that truth has always guided the stories we tell and where those characters go,” said Steve Binder, “NCIS” executive producer, in a statement. “So regarding the future of Gibbs, as long-time fans of the show may have noticed over the years … never count Leroy Jethro Gibbs out.”

Monday’s show was seen by an estimated 7.37 million viewers, the Nielsen company said. That number is expected to increase substantially once streaming and delayed viewing is taken into account, particularly as word of Harmon’s exit spreads.

“NCIS” has been television’s most popular drama for 11 of the past 12 seasons, the only exception being 2017-18, when NBC’s “This is Us” was hot.

Yet it stands as a symbol of another era in television. While the 7.96 million live viewers who watched last week made it, once again, TV’s most popular drama, its audience is older. Five other dramas had more viewers in the 18-to-49-year-old demographic most advertisers crave, Nielsen said.

The show also doesn’t match the buzz or award potential of cable or streaming shows. “NCIS” has never won an Emmy for best drama. It has never even been nominated. Harmon, similarly, has been shut out of the best actor category.

NBC was the most popular network in prime time last week, averaging 6.1 million viewers. CBS had 5.9 million, Fox had 5.3 million, ABC had 3.5 million, Univision had 1.5 million, Telemundo had 1.1 million and Ion Television had 910,000.

ESPN led the cable networks with a 2.92 million average in prime time while Fox News Channel, in its 25th anniversary week, reached 2.25 million. TBS had 2.21 million, MSNBC had 1.17 million and HGTV had 885,000.

ABC’s “World News Tonight” won the evening news ratings race with an average of 7.8 million viewers. NBC’s “Nightly News” had 6.6 million and the “CBS Evening News” had 4.8 million.

For the week of Oct. 4-10, the 20 most-watched prime time programs, their networks and viewerships:

1. NFL Football: Buffalo at Kansas City, NBC, 17.52 million.

2. NFL Football: L.A. Rams at Seattle, Fox, 14.76 million.

3. “NFL Weather Delay,” NBC, 14.75 million.

4. “NFL Post-Game,” Fox, 14 million.

5. “NFL Pregame” (Sunday), NBC, 13.64 million

6. NFL Football: Las Vegas at L.A. Chargers, ESPN, 12.32 million.

7. “The OT,” Fox, 10.24 million.

8. “Football Night in America, Part 3,” NBC, 9.39 million.

9. “60 Minutes,” CBS, 8.47 million.

10. College Football: Alabama at Texas A&M, CBS, 8.33 million.

11. “NCIS,” CBS, 7.96 million.

12. “Equalizer, CBS, 7.67 million.

13. “NFL Pregame” (Thursday), Fox, 7.57 million.

14. “The Voice” (Monday), NBC, 7.48 million.

15. “The Voice” (Tuesday), NBC, 7.21 million.

16. “Chicago Fire,” NBC, 7.18 million.

17. “Young Sheldon,” CBS, 7.118 million.

18. ML Baseball: A.L. Wild Card, N.Y. Yankees at Boston, ESPN, 7.117 million.

19. “NFL Pregame” (Monday), ESPN, 7.1 million.

20. “Chicago Med,” NBC, 7.02 million.