(hypothetically - not saying this is the case yet)
After the given (Moore) we've got Paxton, Felix, Smyly, Iwakuma, Miranda, Gaviglio, Gallardo, and Bergman. Bergman gets stashed in the minors, Gallardo gets traded. That part's easy. (I'm assuming you can't stash Gallardo successfully in AAA).
That leaves 7 options for 5 spots, with 1 'ready' guy at the lower level. We've seen the necessity to keep our options open and our rotation long, so the ideal scenario - assuming again that Moore has forced the issue - is to keep two guys more in Tacoma. This makes Gaviglio a relatively easy demotion. He's ready for next year, or the scenario where we trade 2-for-1 to open him up a spot, but he can't beat out the rest of those guys today.
Who do you pick to lose... Iwakuma, because he's not long for the team? Miranda, because he's got options? It's not Felix or Paxton, and I doubt it's Smyly once he's healthy - we pushed all-in on him, and he's going to be involved. So I think it's a Kuma-Miranda showdown in this scenario... which shows the difficulty with promoting Moore in the first place.
In that scenario, once Smyly proves his health and prowess sufficiently... I'd be hard pressed to demote Miranda if he continues dealing (last game could happen to anyone). But I also hate the idea of sending Iwakuma elsewhere... leaving just Gaviglio/Bergman in AAA. I think I want more than one option I'm excited about down there, and Bergman is back to bing just a bit of a question for me.
All that to say... IMO if Moore comes up, either Miranda goes down or a Smyly/Iwakuma has to have had problems returning to healthy excellence. Otherwise, the Moore+Miranda rotation doesn't arrive until 2018.