We're talking a team that's not a contender, trading simply to make trades makes no sense, it doesn't strengthen the talent base.
And that's what you focus on, when you're rebuilding, adding to your asset base.
If the Phillies were four years away from contending, trading a 26 year old starter for prospects might make sense, but does anyone believe that?
If the Phillies were the Rangers, with excess talent, trading prospects for a key addition would make sense, but does anyone think we're in that situation?
Alfaro and Crawford are not major league starter caliber players this April, maybe by July, maybe by September, maybe 2018. A prospect is just that, a potential player down the road, but there's no guarantee they'll ever make it. So we don't know who will be redundant in a year until their replacement proves they're ready. If Hoskins rips it up, either he or Joseph become expendable, if Cozens rips it up, we don't need a power hitting corner OF, and so on.
We have 7 young pitchers, but most are unproven or injury questions (right now Eickhoff is the only one you can write in for 30 starts). Nola's elbow, Velasquez has never thrown 150 innings, Eflin, Thompson, Morgan, Asher all have questions. So we can't trade them (selling low) and we can't be sure they can be reliable parts of the rotation.
So unless someone makes an offer that Klentak can't refuse, why would you be rushing to trade young players?
Next winter, if Alfaro and Crawford have won jobs, and some of the Lehigh players have proven themselves, then we'll be in the position to make a strategic trade or two that will strengthen the 2018 team. The value of Hernandez, Rupp and Galvis will depend on their 2017 performance, if they merely repeat 2016, their value increases because there's more assurance that's their norm. If they improve, it goes up, if they slip, well, it won't fall that much because for most teams, they're still considered unproven and that will merely confirm that they're only worth a 2nd tier prospect.
So if I'm Klentak I'm staying pat unless someone makes a great offer, in the winter of 2017-18, with more information, I can package Galvis and Hoskins/Joseph and a young pitcher and land a top pitcher or power hitting corner OF or . . . and improve my team, not just shuffle pieces around the chessboard.