It doesn't happen often, but a few TV shows have gone on without the first actor listed in the opening credits. Can "The Office" be one of them?

Television shows lose supporting players all the time — to death (Phil Hartman of “Newsradio”), spinoffs (Jennifer Love Hewitt of “Party of Five”) or a desire to do other work (half of the original cast of “M*A*S*H”).

But it’s far rarer for a show to survive when the first actor listed in the credits moves on. What would “Dallas” have been without J.R.? “Dawson’s Creek” without Dawson? “Everybody Loves Raymond” without Raymond?

Pointless, that’s what. (See “That 70s Show” after Topher Grace moved on.)

So with bona fide movie star Steve Carell leaving NBC’s “The Office” at the end of this season (new episodes begin Sept. 23), fans are wondering if the hit comedy with a faux-documentary style about an inept boss and lackadaisical office staff can survive his departure.

The odds aren’t good. When the star of the show says it’s time to go, it usually means everyone’s out of work.

But if handled with care — and with a little luck — it can be done.

Replacement parts

Several publications have speculated that “The Office” will bring in a new character to lead the wacky supporting cast at Dunder Mifflin.

ABC has some experience in this area, with mixed results.

Michael J. Fox, beloved for his 1980s sitcom “Family Ties,” used his charm to steer his 1990s sitcom “Spin City” to four seasons of decent ratings. So when Fox had to leave his starring role as New York City’s deputy mayor because of Parkinson’s disease, it could have been the end of the show.

But “Spin City” had two aces. One was the star power of Heather Locklear, who joined the cast in time for Fox’s final season. She served as a bridge to Season 5.

The other was curiosity about how future “Two-And-A-Half Men” star Charlie Sheen — a tabloid fixture back then as he is now — would take to TV after a successful but dwindling film career. He helped “Spin City” carry on for two more seasons.

Sadly, “8 Simple Rules for Dating My Teenage Daughter” never quite recovered from the death early in Season 2 of popular star John Ritter. Surviving cast member Katey Sagal and cast additions James Garner and David Spade gave it a good effort, though, carrying the show through Season 3.

Over on NBC, Valerie Harper — for reasons the Internet and more legitimate sources (i.e., books on TV history) can’t seem to agree on — either voluntarily or forcibly, but certainly acrimoniously, left “Valerie,” her late-1980s sitcom about a harried mom.

Perhaps as an antidote, sunny Sandy Duncan came on board as an aunt who took charge of her nephews (including Jason Bateman), and the retitled “The Hogan Family” continued until 1991.

Become something else

The concept of “jumping the shark” comes from an episode of “Happy Days” in which Fonzie jumped over a shark pit on water skis. Not long afterward, Ron Howard left his headlining role on the nostalgic sitcom to become a ridiculously successful film director, and “Happy Days” was never as good.

But enough people tuned in to keep going, so by Season 8, “Happy Days” shifted focus to the budding romance between Chachi and Joanie (despite the fact Joanie coolly deflected Chachi’s advances for several years), and to Fonzie’s efforts to become a grownup while remaining cool (teaching at Jefferson High School, becoming a one-woman man). It was terrible, but “Happy Days” lumbered on for four more seasons.

Not to keep picking on ABC shows, but here’s where things worked rather nicely. “The Practice” planned to wrap up production after seven seasons but unexpectedly was 1) renewed for an eighth year and 2) ordered to cut costs. Half the cast was fired (including series star Dylan McDermott), and the less expensive James Spader and William Shatner joined for the final year. Then the show morphed into the Emmy-nominated “Boston Legal,” and Shatner won an Emmy Award for playing loopy lawyer Denny Crane.

Concept vs. star power

If a show’s concept is solid, the writing is good and there’s a deep pool of supporting players — hallmarks of “The Office” — you can plug in all kinds of characters and actors into a big gaping hole in the cast. This may be where there’s the most hope for fans of “The Office,” who are accustomed to the fake documentary style and a cast of goofy sidekicks who, presumably, will carry on after Carell leaves.

Here’s where it worked.

“Mission: Impossible”: The 1960s-’70s CBS action series made Peter Graves a household name when he played Jim Phelps, leader of the Impossible Missions Force, a band of highly trained government operatives who took on only the most difficult threats to national security. But you may have forgotten that Graves didn’t join the cast until Season 2. Steven Hill played IMF leader Dan Briggs in Season 1.

“CSI: Crime Scene Investigation”: William Petersen’s character, Gil Grissom, leader of crime scene investigators in Las Vegas, was fascinating: secretive, seemingly interested only in work, yet passionate about teaching and bringing others into the world as he sees it. But one reason CBS’ “CSI” survived Peterson’s departure (Laurence Fishburne now headlines the show) is because, ultimately, it’s about using science (and cool, gory camera close-ups) to put bad guys behind bars.

“Law & Order”: Michael Moriarty wasn’t the first person to leave the “Law & Order” cast — just the loudest. As early as Season 2, you started seeing cast changes in what ultimately became a 20-year NBC television crime drama. The list of cast members is enormous — Fred Thompson, Benjamin Bratt, Jerry Orbach, Angie Harmon, Jill Hennessy and the actor most associated with the show, Sam Waterston (Moriarty’s replacement).

But here’s a fun fact: The actor who did more “L&O” episodes than all but three other people was … “Mission: Impossible” castoff Steven Hill. So maybe Steve Carell will be OK.