Don't do that trade. You're giving up two top-20 (arguably top-10 prospects) to get one top-10 player. Fielder has the most upside with his insane power, but Hermida will become a consistent 30-power guy with a good average in the pros, and McPherson's power potential is also considerable. Nippert is not enough compensation for that. On the other hand, if it was something like Hermida+McPherson for Fielder+say...a slightly lower prospect, either due to being lower in development or just worse, period...like Chris Nelson or James Loney, I would do the trade.