I think Rozier is being showcased.
Stevens seems adamant about making Rozier the 2nd unit's PG and giving him a role on the team, when really Smart's at the point in his development where it'd make more sense to give him the playmaking/ball-handling responsibilities (especially with Kelly coming back to share in that, and Jaylen breaking out) and keep him up towards 30 mpg where he's been his first 2 years.
IT 32 / Smart 16
AB 30 / Smart 14 / Green 4
Crowder 14 / Brown 22 / Green 12
Amir 25 / Crowder 16 / KO 7
Horford 30 / KO 18
That's a full rotation right there, and that's already leaving out Jerebko and Zeller. That's also only a regular season line-up, in the playoffs the starters play a lot more.
I really like Rozier, but not as much as I like the defensive intensity and size/length of Smart - Green - Brown on the perimeter. Can't see room for him as a backup guard without stealing minutes that Smart's earned.
I think with Jerebko, Zeller, and Rozier all being expendable, and with Rozier being a valuable prospect on a rookie contract, we can turn that into some sort of favorable trade package.
I guess another option is Brad keeps playing Brown at PF.
IT 32 / Rozier 14 / Smart 2
AB 30 / Smart 18
Crowder 16 / Green 14 / Smart 10 / Brown 8
Johnson 20 / Crowder 14 / Brown 14
Horford 28 / Kelly 20
Or I guess it's possible Brad makes Crowder a full-time 4 and starts Brown.
IT 32 / Rozier 14 / Smart 2
AB 30 / Smart 18
Brown 24 / Green 14 / Smart 10
Crowder 30 / Johnson 18
Horford 28 / KO 20
Any way you look at it, Jerebko is completely expendable, and Rozier is expendable-enough (especially if he comes out hot to start the season).