LOS ANGELES -- Offices change personnel all the time, but when the boss leaves, things can go awry in a hurry.

Could that be the case when Steve Carell leaves "The Office"?

At the Los Angeles premiere of his new film, "Despicable Me," the actor confirmed that he would leave the popular and Emmy-winning NBC show after it concludes its seventh season next spring.

"I just think it's time," he said. "When I first signed on I had a contract for seven seasons, and this coming year is my seventh. I just thought it was time for my character to go." 

Two months ago, when word first leaked about Carell's thinking, Joel Keller of TVSquad.com asked, "Could 'The Office' go on without Carell? Maybe. Though I'm not sure I'd want it to."

Roger Friedman of Hollywoodnews.com disagreed, "If 2011 is the end of "The Office," it's not such a bad idea. Most TV series go on way past their prime."

According to TheWrap.com, NBC has a plan in place for Carell's departure. "Steve has made comments before, and we are not blindsided by this at all. So we are prepared if we need to deal with it."

NBC wasn't revealing the plan, of course, so whether it could involve the promotion of an existing "Office" player or the addition of a new one is unknown.

There are a number of TV series that have survived the loss of big stars. "CSI" is still going strong with Laurence Fishburne, and "Law & Order" was a revolving door of lead actors over its 20-year run. (Even Sam Waterston, the rock of the show, didn't join until the fourth season.)

On the other hand, some TV series immediately lose their footing when a lead performer departs. "Welcome Back, Kotter" was gone almost as soon as John Travolta left. "That '70s Show" only lasted a year after Topher Grace and Ashton Kutcher bowed out; "Northern Exposure" suffered after Rob Morrow took off.

And there were plenty of complaints about "American Idol" (not to mention declining ratings) in its first post-Paula Abdul season. Who knows what will happen now that Simon Cowell's not coming back?