Under questioning today about the new Brian Williams primetime news magazine (which has been reported to be in development, but was not on the NBC 2011-12 schedule announced today, NBC Entertainment chairman Robert Greenblatt remarked that it will go on the NBC schedule "as soon as it's ready".
However, the only way for Brian's news magazine to get into NBC's Fall schedule is if it replaces a show that's already on the schedule, there are no "to be determined" timeslots (forget Saturday, Brian Williams does not do Saturday).
The cynical among us might imagine a more honest answer like "We're sure it will do fine wherever we put it, so we're holding it in reserve to fill the timeslot of the first rookie drama that fails". (Assuming that Brian's show will be an hour, it is impossible to be called in for a single failed sitcom.)
Or the show might be brought off the bench for a couple other reasons I included in the poll.
You be the judge.