It also let’s us get a better look at some of these prospects, to see what we have. I think it’s smarter to be patient and not start trading our big trade chips just yet. Hernaiz was definitely expendable, so I’m really happy with this trade. Ideally, by the trade deadline, Holliday has shown signs that he’s the future at SS and we can confidently trade from our depth at SS to improve our pitching again.
I don't think he's ever going to comfortably part with the top guys in the system until there are clearly established players on the ML team that would actually block those players he'd be looking at trading. For example, I think once Gunnar and whomever of Westburg/Norby/Ortiz/Mayo lock down two spots (and assuming Holliday is ascending), at that point he'll look to trade whoever hasn't earned regular playing time (but is hopefully still maintaining trade value by performing well in AAA). I think he's worried of trading the wrong guys and having whoever he's left with bust at the ML level, especially if it's in pursuit of a pitcher with minimal long-term team control.