My stab at it:
SP (5): Means, Lyles, whoever has a good ST out of Zimmerman, Akin, Kremer, Lowther, A Wells, T Wells (could go back to BP), Lopez, Baumann, waiver wire pick-up (yes i fully expect at least one). So that's 2 locks, barring injury.
RP: Sulser, Tate, Scott, Fry, Baker, T Wells (if not in rotation), Lopez (if not in rotation), Any of those that don't make the rotation above, possibly Bautista and/or Vespi. Vespi may even beat out Fry.
C Chirinos, Taylor
IF Mountyourcastle, Urias, Mateo, Owings, KGutierrez, Odor
DH Mancini
OF Hays, Mullins, Santander, McKenna
Owings and Mateo have OF experience so i think they both make it. Odor is the wildcard, does he make the team?
I think it makes the most sense to keep 15 P and 13 Bats but that doesn't mean that's what will happen.