Detroit actually has quite a few options for the power forward position (the 4). Who they decide to play there may be decided by who they play at center (the 5). Here are some thoughts on this.
Isaiah Stewart, Nerlens Noel, Kelly Olynyk, Marvin Bagley, Isaiah Livers, and Jalen Duren are our big guys. Five out of six can also play center, only Livers is likely not to. Duren is very, very young but needs minutes to develop, and has outstanding athleticism that may win minutes on its own merit. If Noel is healthy he brings similar athleticism and solid defense. Bagley is athletic, but his defense lapses. Stewart is a relentless defender and developing long ball shooter. Olynyk is perhaps an interesting blend of all of these abilities. Livers has shown he deserves to be given a chance to become a very good stretch 3-D role player at the 4.
Although it seems likely Duren won't start, he should see an escalating number of minutes at the 5. I anticipate that Noel and Bagley will split time as the starter. Olynyk seems to be lurking around the corner, but I anticipate he will be viewed as a swing player that slides in to the 5, when necessary from the 4.
I think that I would try Stewart with Livers as our primary 4 rotation. As a I said, Olynyk will be used here too, but I think the team will want to give the youngsters more time to develop, than not.
Recapping the use, with some minute projections over the first 30 games:
PF Stewart 26, Livers 15, Olynyk 7
C Noel 18, Bagley 20, Duren 10
Over the next 30 games it will perhaps move to something like this:
PF Stewart 24, Livers 18, Olynyk 6
C Noel 14, Bagley 20, Duren 14
Over the final 22 games this may happen:
PF Stewart 24, Livers 20, Olynyk 4
C Noel 12, Bagley 20, Duren 16
Subtle shifts but Duren will get more and more time, as will Livers. Stewart will be asked to be a powerful force when he's on the court, and be the primary rebounder.