Thinking more about it, it's a curious trade. The established big leaguer is a lottery ticket, and the AA pitcher feels like we know what we're getting, although his excellent 2019 points to some upside.
But it almost has to be a good trade. Relievers, even good ones like Workman, just aren't worth much to a bad team. In contrast, controllable starting pitchers are worth a ton to us.
We have some interesting position player prospects in the high minors (Downs, Duran, Dalbec, Wong), really most of our pitchers (except Mata, really) are either probable relievers unless some real development happens (Houck needs an approach to LHH, Thad Ward needs more reliable command) or have various other impediments (Song is in the Navy, Groome needs like 100 more IP before we can really begin to tell what we have with him).