Well, actually, he doesn’t hint it, he says it outright. But there’s enough wiggle room in there (“probably” and “I don’t think so”) that he could wind up staying longer. Still, this is unusually unambiguous:
Question: How long will you stay with The Office for? How many more series? How long does your contract run?
Steve: Contract through next season.
Question: And will you stay after that?
Steve: I don’t think so. I think that will probably be my last year.
As I say, this doesn’t actually rule out his deciding to extend his contract, but it does at least show that he’s seriously thinking about leaving and is willing to say so. No one could really blame him if he wants to leave after making (including next season) around 140 episodes. Like George Clooney, he’s built up his career in the right way, sticking with his hit TV series while taking the summers off to make bad movies (plus the occasional good one like 40 Year-Old Virgin); now comes the second phase of such a career, leaving the show and trying to see if he can actually make some good movies.
Would the show actually go on without him, if he does leave? I guess it depends on how NBC is doing by this time next year. As things stand now, The Office is one of the few decently-rated comedies it has (the two new shows on its Thursday night lineup are good, but not popular yet, and 30 Rock will never be popular). It has enough audience goodwill toward its large ensemble cast that it might be able to go on for a year without Carell; it wouldn’t be the same, but it wouldn’t be a completely different show, either. Some shows have to shut down if the star leaves; Cheers ended when Ted Danson decided he didn’t want to do another year. But The Office is more about the entire office than Cheers was about everyone who hung out in the bar; the characters are not primarily defined by their relationship to Michael. So I can definitely see the network deciding that a Carell-less office would perform better for them than another comedy they could put in its place. Because that’s probably true.
Also, isn’t it cute they way they say “series” when talking to North Americans, and we say “season” when talking to British actors? Forget world currency or one world government; we need one English word for a batch of TV episodes.