Tuesday, April 27, 2010

Chris Ianetta, Miguel Olivo, and the Problem of Sample Size

Chris Iannetta's demotion today is far from the most disappointing news in Rockies-land recently, what with injuries to Brad Hawpe, Jason Hammel, and now Jorge De La Rosa, and, of course, the still shocking death of team President Keli McGregor. Nevertheless, Ianetta's demotion is troubling for the same reason that Seth Smith's continual lack of playing time is troubling. A franchise that is doing so much right in so many ways (a tip of the cap to McGregor, here, who was a huge part of the way the Rockies were built) continues to misunderstand sample size, player roles, and, in general, how to put the best nine players in the organization on the field each day.

I will not deny that Miguel Olivo is off to an excellent start. In his first 47 PAs this season, he's wracked up 14 hits, 5 of which have gone for home runs. He plays a competent defense, and his utter inability to draw a walk has so far not been troublesome. Even so, Olivo has 16 strikeouts to his 14 hits, and he has so far been incredibly lucky on those rare occasions when he's put the ball in play without hitting it out. In short, while he may be hitting .310 now, 47 solid plate appearances does not tell us more than years and years of incompetence at the plate. Olivo, for all the power he has displayed in his career, has a career high OBP of .292 (and for the batting average fans out there, his career high is .263, which is well above his career average of .244). Yeah, .292. As in, in his best season - last year - Olivo made an out an astounding 71% of the time he came to the plate. For a point of comparison, Ubaldo Jimenez - a good hitter for a pitcher - put up an OBP of, you guessed it, .292 last season.

Granted, Olivo hits more home runs than Jimenez, and is obviously a better hitter for that reason alone. There's also reason to believe he'll be boosted somewhat by playing half of his games at Coors Field, and he could very well launch 30 home runs this season if he plays regularly, even though he'll probably punch up a .250 batting average and an OBP under .300. It's worth noting that the Rockies already have a .290 OBP, 20-30 home-run hitting, strike-out machine in Clint Barmes (who is, at least, one of the better second basemen defensively in the league), why do they need Olivo to produce outs, too?

As for Iannetta, there's no denying he's off to a slow start, despite the walk-off homer he hit a little over a week ago. But do Iannnetta's 34 plate appearances really constitute a trend? For one thing, Ianneta has been unbelievably unlucky so far. Of the 17 balls he has put in play (non home-runs, strikeouts, or walks), a measly 2 have fallen for hits. In general, about 3 out of every 10 balls in play drop for hits, so with even average luck, Iannetta's putrid .118 average should be above .200, at least. And, as always, Iannetta's value comes from power and walks. He'll never be a .300 hitter, but last season, despite a .228 batting average, Iannetta's OBP was .344 (against the league average of .331). That is, Iannetta made an out a full 1% less often than the average hitter in the NL, and a full 5% less often than Miguel Olivo.

Even in 2008, when Iannetta produced a career high 18 home runs, along with a .264 batting average and a .390 (!) OBP, the Rockies have insisted on starting other catchers regularly. It is certainly beneficial to have more than one competent catcher, because the position is the most tiring in baseball, but as with Yorvit Torrealba, the Rockies are mistaking some mysterious intangible quality of Miguel Olivo's for actual skill and usefulness, and are relegating Iannetta to a backup and, now, minor league position. There is every reason to believe that Iannetta will not be a Sky Sock for long, but that he has been demoted at all suggests that Olivo will get the majority of starts throughout the year, even after he regresses to his usual, futile self.

What I haven't made explicit here is the difference in how I am understanding the numbers and how, apparently, the Rockies front office is. When I look at Olivo and Iannetta, I look at the last two or three seasons of their respective careers. There is no question, given those larger samples, that Iannetta is a superior player to Olivo in every way. I would wager that, given the chance to start regularly, Iannetta would even hit more home runs than Olivo (all the while posting a .350 OBP instead of a .290). But apparently that analysis isn't happening with the Rockies. They see 30 at bats for one player, 45 for the other, and are drawing conclusions from there not about who has been better so far - it's clear that Olivo has been - but who is going to be better moving forward.

One of the fundamental insights of sabermetrics has nothing to do with which statistics are better or which skills are repeatable and which luck. That insight is that baseball teams should make decisions based upon what they think is going to happen, not on what has happened before. The Philadelphia Phillies, in signing Ryan Howard to a 5 year, $125 million extension yesterday, are paying for what Ryan Howard has already done, not what he is going to do. There is little reason to believe he will be worth a $25 million salary when he is 36 years old, even if he potentially was when he was 27 or 28.

Likewise with the Rockies (though at much less cost): Miguel Olivo's hot start is a blessing, and there is no question he is a useful backup. But Iannetta is younger than Olivo, he has a significantly higher career OBP, and he has just as much power. There is every reason to believe that, moving forward, he'll be the better player. Even so, over any given sample of 40 at bats, Olivo might hit 5 homers and Iannetta hit .120. But, and here's the key, over most samples of 40 at bats, Iannetta is going to be the better player.

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