Stroman for Gray doesn't make any sense. We'd only be adding a year of control (unless his demotion in '18 added a year), which won't really mean much for the team as is. It would make more sense to try to acquire Gray without giving up Stroman, that way either we get lucky and the team becomes good earlier than expected, or we have two trade pieces that we can trade some time in the next 1-2 years at hopefully higher value. Of course, the Rox might insist on Stroman, but I'd see if they would take Sanchez first (no guarantee he's even a Sp long term).
I agree though I think a deal can be had here with the Jays and Rockies.