"Shelby has the best combination of power and speed in the system. Though he's only 5-foot-10, he's strong for his size. He adds to his plus speed with good baserunning instincts and could develop into an even bigger stolen-base threat. He's improving in center field and has an average arm."
He'd go on to repeat his success at A ball at high A in 2008, posting a .858 OPS with 15 home runs and 33 stolen bases. It was the sort of performance that would've had me touting him as well - as well it should. But when challenged by AA pitching, Shelby folded, unable to adjust to the more advanced breaking pitches.
It's also a sort of case study in precisely why I grade players who have proven their ability to have success at the upper levels of the minors so much more aggressively than other lists, even if that ability is perhaps far less exciting than that of a younger player. A player like Shelby (or anyone else for that matter) can have all the tools in the world, but until those tools translate into skills at advanced levels, it's still a huge crap-shoot.
Lots of teams have players like this. Here in the Central the Tigers have Daniel Fields, the Twins have Joe Benson, the Indians have LeVon Washington, the Royals have Brett Eibner, and the Sox new power/speed outfielder is Jared Mitchell - all of whom fit the mold in different ways and all of whom are very intriguing, promising prospects. Yet with the exception of the Twins Benson, absolutely none of them have proven anything beyond A ball.
As scouts, we love guys like this (and all the guys I just listed were pretty high draft picks). We're tantalized by what they could be. Fast legs, strong frames, quick hands, good bodies... what's not to like? But it's also the players like Shelby who are precisely the rationale for why I don't rank players like this higher on my lists. Obviously I know what they could be, I'm not blind after all. But tools do not inherently equal baseball skills.
Corey Ettinger is a Senior Writer for Baseball Digest as well as a proud contributor to both 612Sports.net, 312Sports.com, and 313sports.com. He also provides extensive analysis of the American League Central Division at his own blog, AL Central In Focus. Be sure to follow me on Twitter @Coreyettinger for the latest updates, random thoughts and general tomfoolery.