I've learned a lot from reading Baseball Prospectus for 12 years, but the most useful thing, as a writer, is how they produce their front-cover teasers—the little fortune-cookie-fillers that sit across the middle of the cover, under player headshots but above the blurb from Billy Beane. It's the showstopping Baseball Prospectus magic trick, and it's so easy: You take a guy who had a better or worse season than everyone expected, and then you say his season will probably be worse or better this year. It's applying the benefits of regression to your writing without the costs, which mostly involve explaining regression to yourself and others.
Aledmys Diaz had a bad year, after several murky good ones, but the worst thing about his particular bad year was that it gave us no new information about a player who had very little to offer in the first place. (Joe Schwarz helpfully gathered what there was back up yesterday.) It's not like that with the other second-tier infield prospects. When Breyvic Valera was 22 he was putting together the emptiest possible .313 average between Palm Beach and Springfield; when Jacob Wilson was 22 he was hitting in Peoria, and then not hitting in Palm Beach.
When Aledmys Diaz was 22 he was performing a year's penance for pretending he was 23. Wilson's entire professional career—they were born a month apart—fits neatly inside the time Diaz has lost since his last season in Cuba, and looks a lot like you might have expected Diaz's to look.
What do you do, on your Baseball Prospectus cover, with somebody whose season wasn't better or worse so much as empty?
Aledmys Diaz's first season was surprising because it seemed so irrelevant; like all good Baseball Prospectus reversals, what we can actually take from it is the Chinese-curse certitude that players are rarely surprisingly anything two years in a row.
Something will happen to Aledmys Diaz this year. He will show that he's a prospect worth offering $8 million, or he will show that he isn't. If he vanishes again he'll vanish more forcefully. But for now—for the purposes of your Baseball Prospectus reversal—he is more invisible than he ought to be, and thus available to make you seem like a wizard to people who haven't thought about him since he signed his contract.
I have no reason to be optimistic—the point is that I have no reason to be anything, except aware—but I am. All that's left pulling the Aledmys Diaz bandwagon is the information communicated by the Cardinals' original investment, but most first-rounders (non-Kozma division) get a year or two further on that tank of gas.