Someone will likely get hurt or perform poorly enough for at least one of Cowser or Kjerstad to get legit run. But until then it's not ideal imo.
As for Holliday and Mayo, I can't imagine them bringing up the former without a ton of expected playing time, but Mayo is more interesting and challenging, at least if Holliday is also up. It's not hard to carve out some time vs lefties, but otherwise it's a question of where do they want him to play and who are they good with taking time away from. If I were Jordan Westburg, I might be a bit pressed to get off to a good start.
Holliday will surely play every day once up, he will get the Gunnar/Adley treatment, and he should. I'm not sure if Mayo will get that too, I think this year at least will be tough. I'm going to assume Mountcastle doesn't really lose any PT, though I suppose he could. I hope Westburg proves that he shouldn't either, but he seems like the most obvious first odd man out. That assumes Mayo can play 3rd though, which I guess isn't clearly confirmed yet.
The offseason will again be interesting. I can't imagine going into next year without any trades, unless some people prove they don't belong. The best case scenario where everyone looks like a major leaguer will make things interesting and difficult.
