If you guys read sites like TVByTheNumbers, their theory is that while cancellation is still possible, its likely that Sony, who produces the show, will sell the 4th season to NBC dirt cheap so that the low ratings aren't hurting NBC's bottom line. This will enable Sony to produce the number of episodes necessary for syndication in the 4th season, where the real money is for them. I think this is what they do with Brad Garrett's sitcom Til' Death. It got a 4th season without even airing all of its 3rd season.
I'd almost guess NBC burns off the remainder of Season 3 between Spring and Summer, and then shoves Season 4 on an odd night like Friday or something next season or uses it as a midseason replacement.
I'm assuming Tina Fey and Amy Poehler won't be pregnant for the next season of their shows, so you're pretty much looking at Up All Night, Parks & Rec, The Office, and 30 Rock as your Thursday night lineup unless Up All Night totally bombs in its move to Thursdays this season. I don't think it will, but you never know. 30 Rock wasn't exactly a ratings smash at 9:30 or 10, which is why I think they're trying it at 8 PM. Point of all this is - there isn't going to be room for Community to be a featured show next season on Thursdays, so my guess is odd night or mid-season replacement.