Castro is a nice piece, but he is nowhere near the kind of player you worry about "wasting" his cheap years. Why not? He's already about a 4 win offensive player right now at age 21 and should only increase his power in the next couple years (and already has taken a step up from last year). I'm not saying he's for sure going to be a superstar, but given what he's done so far, it would be stupid to say he is nowhere near that kind of player. If by "4-win offensive player" you mean "on pace for less than 3," sure. And his defense is still a problem. Edit: Well, let's say "on pace for about 3," depending on what site you use.