Given that he is using the auspices of the PGA Tour to make his announcement tomorrow, it would seem likely that he will be announcing that his comeback will be at a PGA Tour event.
And given that his agent, Mark Steinberg, said that the tightly controlled, no-questions-accepted media event could not wait until Monday, I wonder if he isn't planning to play next week in the Waste Management Phoenix Open. He would have to commit by the end of tomorrow, so maybe that's why the rush.
The irony in that is that the Phoenix Open is maybe the one non-major that has done fine without him. Woods hasn't played the raucous venue in a few years, but the crowds keep coming and their noise keeps making it one of the noteworthy stops on the tour.
We'll know tomorrow about this time.