In the comments, Chileburger asks about the meaning of the strong performances by upper-minors pitching prospects Rudy Owens, Jeff Locke, Justin Wilson and Bryan Morris, and how to square those with my pessimistic assessments of the farm system.
I'm happy to see these players perform well, as I'm happy to see Pirates players in general do well, but they don't have a tremendous impact on the overall health of the farm system. Of the four, the only one who appears to have a reasonable shot at being an impact player is Wilson, and that's if you really stretch the definition of the word "reasonable" -- his erratic control is likely to continue to be a problem.
Owens and Locke both lack shutdown stuff, and while they've both done great jobs limiting walks at Class AAA this year, both of them have rather low strikeout rates, with Owens at six per nine and Locke at about 6.7 per nine. Not to put too fine a point on it, but those aren't the kinds of numbers typically associated with big-league success, regardless of how good their ERAs might be. The ability to limit walks against AAA batters is a good one to have, but it doesn't necessarily portend big-league success. (Just ask Brian Meadows, who struck out 40 batters and walked zero in 51 Class AAA innings in the Bucs' system in 2003.) Before the season, ZiPS compared Owens to Eddie Priest, Bobby Livingston and Abe Alvarez, three players who basically maxed out in the high minors. This isn't to say that Owens can't be better than those players, but without a big change in his career path, he's probably just a back-end starter.
Morris is, at this point, a reliever, which is fine, but nothing to write home about. His numbers so far this year are good, but hardly eye-popping. Functional, but non-elite, relievers are always nice to have, but they aren't generally that hard to find, either.
These four players are known, collectively, as the Altoona Four, but that's probably a nickname we should retire. There's an entire disappointing year separating them from their Altoona performances at this point, and it's no accident that they're all still in the minors as they head into their mid-20s. With the possible exception of Wilson, they currently all profile as depth, with the chance to become something a bit better than that. That's nothing to sneeze at, and if the Pirates continue to have injuries in their starting rotation, or they end up trading someone, I'm sure I'll appreciate the knowledge that the Bucs have so many pitchers who are capable of filling spots. And all four guys look likely to have big-league careers of some kind. But to me, they aren't the kinds of players who make the difference between a decent system and a terrific one.