Projecting Wieters' rookie season

March, 4, 2009
Can Matt Wieters really be this good? Baseball Prospectus' PECOTA projection has Wieters finishing the 2009 season with (among other things) 31 home runs and 102 RBIs. Really?

Here's Steven Goldman on the dramatic numbers:

    PECOTA is an essentially conservative program. Its player-performance projections are neither wildly optimistic nor pessimistic, but built purely from the data, and from its own understanding of the way that player careers progress based on literally thousands of antecedents. Thus, when it proposes that Orioles catching prospect Matt Wieters, a rookie-to-be who has never played above Double-A, could hit .311/.395/.544 in the majors this year, we took notice -- this was the first time that PECOTA had looked at a prospect and predicted an MVP-caliber, Hall of Fame-level season right off the bat.

    By way of comparison, consider the two players who were the 2008 Rookie of the Year Award-winners in their respective leagues, both of whom PECOTA quite liked from the get-go. Tampa Bay Rays third baseman Evan Longoria received a weighted mean projection of .266/.339/.459. This was no surprise; by acclamation, Longoria was one of the most talented young players in the game. However, PECOTA can only go by what it sees in the player's profile, both in terms of performance and vital statistics, so though it was quite high on Longoria compared to most other prospects, it did not overstate its estimation. In fact, PECOTA proved to be a little too reserved in this instance, as Longoria hit .272/.343/.531 -- the projection model nailed the batting average and on-base components of Longoria's rookie year, but missed low on his power.

    Over in the senior circuit, Cubs catcher Geovany Soto was projected to hit .273/.352/.470, another enthusiastic projection, but still a bit short of historic as far as introductions go. As with Longoria, PECOTA anticipated a bit less power than Soto displayed in major league action, but was quite close on the other two legs of the production tripod, as Soto hit .285 while posting a .364 on-base percentage. Soto had had an explosive year in the minor leagues in 2007, one almost as impressive in its own way as Wieters' breakout campaign, but it was one that because of Soto's age, the context of the league and performance levels involved, and other factors did not receive the same rave review from the system.

    These same factors are the key to Wieters' stunning PECOTA projection. PECOTA does not take a prospect's minor league stats as is, but translates them first, adjusting for the park and league context. It also considers the player's age, position, and body type before making its projection. The key for Wieters is just how well he makes out, despite the discounts on his performance wrought by these various translations. It is the rare young player who towers above his league to the degree that Wieters did last season, and then goes further by making the difficult jump to Double-A, not only maintaining production, but actually accelerating it. It is the rare 22-year-old who bats .345/.448/.576 in High-A ball, let alone .365/.460/.625 at Double-A. No matter how aggressively one reduces Wieters' numbers through translation, you simply can't make all of that go away.


    Of course, as we've often said in our annual book, PECOTA is not destiny. Much stands between a young player and the achievement of his projection, whether that projection is as boldly put as Wieters' is, or merely average. Injury is a particular risk for a young catcher, as an errant foul tip can mangle a finger, or a contact play at the plate can mangle an entire body. What makes Wieters' projection all the more impressive is that PECOTA is aware of the toll that catching can take on a backstop's offensive skills, and yet it still sees such impressive short-term results for the Orioles tyro.

    Perhaps, then, it is wrong to say that PECOTA lacks optimism, that it doesn't rave. In its own way, Wieters' projection is its way of saying, "Hey, I think I spot a very rare talent here; you might want to pay attention." Then again, PECOTA is merely a computer program, and this interpretation is, appropriately, an act of translation.

Sorry about the long excerpt, but this is important.

Add Wieters' on-base and slugging percentages and you get (roughly) a .940 OPS. Last season, a .940 OPS would have been good for fifth in the league, just behind Kevin Youkilis and well ahead of Aubrey Huff. Given the difference between Fenway Park and Oriole Park, we can slot in Wieters' (projected) projection at roughly the same level as Youkilis' 2008: 143 OPS+ (adjusted OPS).

Since 1901, there have been 62 catcher seasons that included at least 400 plate appearances and an OPS+ higher than 140. I suppose that 62 seems like a lot, but there have been a lot of catcher seasons in the last 108 years. And of course we're not talking about 62 different catchers; Mike Piazza alone accounts for seven of them.

Then there is Wieters' youth; he turns 23 this spring. If we refine our search to catchers younger than 25, our list becomes a great deal smaller: seven seasons and six catchers (including Johnny Bench twice). However -- and this is really interesting -- two of the six catchers are active right now and were younger than Wieters when they did what they did.

It happened three years ago. In 2006, 22-year-old Brian McCann and 23-year-old Joe Mauer posted nearly identical OPS+ figures (McCann 143, Mauer 144). Mauer had played only 40 games above Double-A (five in Triple-A, 35 in the majors); McCann skipped Triple-A completely, but played 59 games with the big club before his breakout season.

I would be a bit more optimistic about Wieters if he'd already racked up a bit of service time with the Orioles; if he'd gotten the hang of the locker room and the big crowds and all the reporters at his locker after the game. But he has already established himself as exceptionally talented, and I think it would be foolish to assume that he won't at some point hit those numbers that PECOTA thinks he will.


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