Not sure this timeline is accurate. Gausman couldn't find a spot early in the year, before Gonzo got hurt and before Norris was banished to the pen. When Gonzo got hurt, Gausman came up, and he stayed up and Norris went to the pen when Gonzo returned (Gonzo on DL June 10, Gausman first start June 20, Gonzo return June 25, Norris last start June 29). Gausman was skipped twice after that first start and worked around the AS Game, so he was bounced around a bit but was mostly roster management stuff because he had options and they didn't need all 5 SP over that stretch (the worse thing was not getting him a start until 6/20).
I don't think there was ever a point in time where Gausman wasn't in the rotation while they were asking Gonzalez to pitch through discomfort (if they ever did that).
I'm saying that this "discomfort" has been all season. Hence the DL back in early June. Like I said in my little one off earlier, whenever you see a DL thing like this, it's been going on for a WHILE that we don't know about, and either it gets to the point that they beg off, or the results become SO bad that you can't just ignore it and let them pitch through it. I think the latter happened here, but I'm willing to bet this stiffness/soreness/discomfort has been there since May at least.
They should have sent him to rest on the DL for an extended period and just moved KG into the rotation back in May. This is just one example of the shuffle all season, my main point is that they kept trying to make room for this depth and marginal starters when they should have been developing Gausman from the beginning of the season at the ML level.
It's just now at this point you can say, well they tried and we missed the playoffs because of it, so if you disagreed from the start, you weren't wrong.