One scenario I think it's plausible, is that as soon as we have the #2 seed locked up, and if we lose 1 or 2 of the games left against GSW, Pop is just going to shut down Tony, Manu and Tim. Not completely, but big bouts of rest. During that time, all of Miller, KMart and Boban are going to have plenty of minutes to show what they have, get acclimated, and allow Pop to make decisions as far as who to count with for a shorter playoff rotation.
Frankly, I don't think Simms, Kyle or Boban have shown they can be thrown into the fire in the playoffs this season, tbh. In that sense, depending how he looks, Martin makes a lot of sense as the backup wing
TD21 was talking about all season long. Miller I think it's more like insurance in case Tony or Manu get dinged up (especially the latter, depending on how he looks from here until the playoffs).