The issue is the Jays are one Scherzer thumb explosion away from having a very messy rotation situation, especially if/when Lauer comes back down to earth. I want no part of counting on Manoah to help out (if he does, then it's gravy). So while I agree the Jays need to add someone better than their existing SP's, I think they may need to add a SP period at this point. The best one they can realistically get.
I don't think Ryan will be traded, and Cabrera left his last start with elbow discomfort (plus he has no history of durability which Atkins generally likes), so to me it comes down to Sandy or Keller. If they just want a rental to eat up innings, then their options grow a bit.
If the Jays go into the final two months hoping for Scherzer to stay healthy, Lauer to remain this good, and Manoah being good enough to fill in the cracks, then that's a massive ask, IMO. Could happen but not something I'd want to bank on.