Well, Fox will probably employ the strategy they're using his midseason.
Move American Dad to 7:30, then air the new series at 8:30 (since the Cleveland Show is moving to 9:30 this midseason). If the new series outperforms what American Dad was doing, go with the new show and axe AD. If it doesn't, burn off the rest of the new series' episodes at 7:30 and move American Dad to 8:30, keeping it instead.
That's what they're doing with Sons of Tucson this midseason and they kind of did the same thing with Sit Down Shut Up and King of the Hill last season, but since the Cleveland Show was waiting in the wings they didn't keep King of the Hill either.
American Dad hits the 100-episode syndication watermark at the end of this season and it's the lowest-rated on Animation Domination now, so it will be the one moved around for experimentation, and I think its fate kind of hinges on if Fox finds a new, higher-rated series in its place.
Another option is that since their Friday night is tanking so horribly right now, they could try airing two animated sitcoms there for the first or second hour. The problem is, that Friday night is so bad that it's just about as tough as the 7:00 hour on Sunday nights, and the shows probably wouldn't be cheap enough to justify putting on Friday.
But since both this Jonah Hill and the Seth Green series are so early in development, it might be jumping the gun to say they'll both make it to TV, they've both still got a ways to go.