You can't really hide a reliever these days, and probably especially not this season. Though they sure managed to hide David Hale!
I can't imagine Holder is anywhere near the player Galvis was. Freddy was a plus major league defensive player at 22, albeit playing 2B.
But it doesn't matter. Maybe we have a young Andres Blanco, maybe we have a young Wilson Valdez. Either way they can spare the 40-man spot for now, and if he beats out Torreyes etc. no big deal either way. You do have to think Barber (and even Girardi) signed off on him.
And I don't think it tells you anything about the Phillies other plans (not to mention the guy making decisions today isn't the one who will be making them on Monday). Right now, they haven't re-signed Didi, and they haven't traded Segura, so why not improve the depth?
That said, Didi certainly isn't coming back if any other team offers him a multi-year deal, or more than he made last year.