Here's Wait 'Til Next Year's list of the top 75 prospects in baseball (via Primer). As we might expect, there aren't a lot of Pirates. Neil Walker is at #44 and Andrew McCutchen gets an honorable mention. WTNY author Bryan Smith is probably more excited about these guys than I am, though. I like Walker a lot, but I'll wait to get too excited until I see how he returns from his injury. Smith says:
Neil's ceiling is in the superstar category offensively... However, before I get too excited, I will have to see more than 20 walks in a season. Since there are very few other offensive problems to refine, I do think this is a problem that Walker can overcome in the next 2-3 seasons.
I think he probably can, too, but I question whether the Pirates will encourage Walker to improve his plate discipline.
I've seen some Pirate fans write that McCutchen is comparable to Marquis Grissom, but that's not right. Grissom has never walked more than 52 times in a season. Grissom's lifetime OBP is .318. McCutchen's upside is a much, much higher OBP than that. His plate discipline is already outstanding, and it'll stay that way if the Pirates don't try to ruin it.