Here's my prediction.
Reds begin Chapman as a set up man in the bullpen. They announce that they are leaving the door open to starting him later in the season.
When Broxton has a couple of bad outings, Chapman takes over as closer and does not start.
That's what I expect. Personally, I'd rather the Reds decide one way or the other. If it's the pen, let Aroldis close from the outset, and you have a great bullpen like last year.
Hopefully Leake has a good year as a starter.
Hopefully Cueto doesn't pull an oblique in the playoffs this year.