I mean it's not like there are 15 other teams that are selling assets, most superior to what the Phillies have to offer.
Hernandez has value, but right now he's just off the IR, no team in a pennant race is going to make a big offer until they're comfortable that he's healthy and back in a groove,
if they have to wait until September for him to play well, why trade for him now?
Timing is everything in life.
As far as the Hellickson deal, Phillies were victims of a screwball, but note they were the SECOND option, i.e.., the fallback, Hellickson wasn't in that great of demand:
You don't strip your ML roster to add a bunch of marginal A ball prospects, now if someone is offering a blue chip (i.e. someone who'd be in our top 5) that's another story.
But whats the point to adding a bunch of A ball guys in August rather than December?
My whole point with players like Rupp and Galvis is that the only way you get good value for unproven players is to play them and hope they perform well enough to raise their value.
Given their inital relatively low value, trading them for scraps make less sense than gambling they can play well enough to garner real prospects.
If Galvis finishes strong, he'll be far more valuable in December than he is right now, while if he doesn't, you can get the same marginal prospect in December you'd obtain now.
If Rupp has a hot finish, and raises his OPS to .725+, he'll have more value than last year, b/c he'll be established as a solid #2 C, if not, well, it wasn't like he was a hot commodity last July.
The players who could bring a big return, Nola, Altherr and probably Williams, are untouchables for a rebuilding franchise.
Everyone else - well, there's a reason the Phillies have the worst record in baseball!