Team        Park                     2009  4 Year
Angels      Angel Stadium             110   96
Astros      Minute Maid Park          104  108
Athletics   McAfee Colisuem            95   92
Blue Jays   Rogers Centre             105  108
Braves      Turner Field               90   95
Brewers     Miller Park               108  106
Cardinals   Busch Stadium              86   84
Cubs        Wrigley Field              97  103
Devil Rays  Tropicana Field            99  101
DiamondbacksChase Field                89   98
Dodgers     Dodger Stadium            104  105
Giants      Pacific Bell Park          75   79
Indians     Jacobs Field               95   99
Mariners    Safeco Park               109  101
Marlins     Dolphins Stadium           98   98
Mets        Citi Field                 91   91
Nationals   Nationals Stadium         109  115
Orioles     Oriole Park at Camden Yar  73   85
Padres      PETCO Park                109   99
Phillies    Citizens Bank Park        105   88
Pirates     PNC Park                  110  106
Rangers     The Ballpark at Arlington  98   97
Red Sox     Fenway Park                98   91
Reds        Great American Ballpark   121  108
Rockies     Coors Field               103  115
Royals      Kaufman Stadium            73   80
Tigers      Comerica Park              94  101
Twins       Metrodome                 109   97
White Sox   US Cellular Field         115  115
Yankees     New Yankee Stadium        130  130

Strikeouts, observed that great philosopher Crash Davis, are boring—and they’re fascist. Strikeouts minimize the need for defensive play, thus taking the fielders out of the game. If we want to live to see the end of the Dave Kingman generation, we need to take deliberate actions to bring about the end of it.

There's something to be said for Conventional Wisdom. In this case, the Conventional Wisdom was unanimous: the three best pitchers in the league were Lincecum, Carpenter, and Wainwright. But in a field as traditionally conservative as award voting, isn't it healthy to allow room for just a bit of unconventional wisdom, too?

Carroll and Law didn't do anything crazy. They looked at the same numbers available to everyone else, and came up with slightly different answers. They should not be reviled for this. They should instead be applauded.

Felipe Alou is really Felipe Rojas. A mistake was made on his first contract in which the scout put in the family name of his mother rather than that of his father. Felipe made the name "Alou" so famous that his younger brothers Matty and Jesus adopted it when they came to the U.S.. The "Alou" brothers have a half-brother from their father's first marriage, and he had a son who also went on to the major leagues. That son was naturally raised under the family name of Rojas name back in the Dominican Republic. That player was Mel Rojas, who pitched 10 years in the majors. Matty Alou in particular still goes back and forth between his two last names depending on which country he is in or what he thinks the situation calls for. "I use 'Alou' when I call the airlines for reservations, because I get a better seat."

Though old players may not be what they once were, the evidence indicates they can still be valuable. According to my estimates, a hitter who has a .900 OPS at his peak would be expected to post around an .850 OPS at 35; a pitcher with a peak 3.5 ERA is expected to post around a 3.75 ERA at 35. Yes, age saps athletic skill, but the stock of skill being diminished is also important.

Is this true?

Let's look at Bradbury's original study (unless you subscribe, it costs about $30 to download). He says:

The results indicate that both hitters and pitchers peak around age 29. This is older than some estimates of peak performance, but it is in-line with the general understanding of human physiological function. ... For [linear weights],which is not normalized for playing time, players peak at 29.41 years. This is similar to the peak-age estimate of 29.13 for OPS, which is normalized for playing time.

How can we test this theory easily? Well, if peak age is 29, we should see players at age 29 have a higher OPS than they did at an earlier age, right? Some may (rightly) note there is a selection affect in who gets to play in successive seasons, and due to regression to the mean we should expect to see players decline from one season to the next - players who underperform are less likely to play in a successive season than those who overperform.

So let's take those players who were 29 in 2008 and compare them to how they did in 2006 at age 27. Thirty-five position players were 29 in 2008 (based upon age on July of that season, the same age criteria used in Bradbury's study). Of them, 27 also played in 2006. What we see does not seem to support Bradbury's conclusion - on average, players lost roughly .014 points of OPS from 2006 to 2008. That's not what we should expect to see if the average peak age is in fact 29.

Something that should also be noted - 43 players were age 27 in 2006. So a little over half of those players stuck in the league to age 29. (Of course, some of those players could have missed a season due to causes like injury or a demotion and could have returned in this past season - I don't have 2009 stats in my database yet.) We're looking at the survivors.

But that's just a one-year sample, right? What if we looked at all age 29 seasons from 1997 to 2008? (As for why 1997, I shall explain shortly.) We see a similar (but less pronounced) dropoff, of about .006 points of OPS.

And of course baseball isn't all hitting. The Baseball Databank has outfield positions broken down from 1995 on (and 1995 plus two years is 1997 - see how that works?)

What we see as that as players grow older, they move off the more important defensive positions (catcher, shortstop, center field) and move to the corners. Thinking of peak only in terms of hitting is not instructive if we want to figure a player's free agent value - defensive value needs to be considered as well.

Bradbury's model may do a good job of explaining in retrospect where peak age is for players who make it to age 35. But it does not seem to have a lot of predictive value for what will happen to a 27-year-old player going forward. Anyone looking to predict future performance should look to some other method of estimating the effects of age.

UPDATE: Here's another way of looking at the issue. Bradbury's study included all batters who debuted past 1920 and played 10 seasons between age 24 and 35. Now, looking at all players who debuted past 1920, 48% were out of the league before the age of 29, Bradbury's purported peak. Does that make sense to anyone? Or flip it around - the most common debut age for a baseball player is 23, and the average player who debuts at that age will play six years, or until age 29. In point of fact, if we look at the most common debut ages:

So, for player that debut from age 21 to 26 (that's 75% of players), the average career length takes them through their age 29 season. Either MLB teams are all highly irrational, discarding players the second they've reached their peak (when given the aging curve Bradbury proposes, a typical player should still have several productive seasons post-peak) or Bradbury's study is simply wrong.

OMAR VIZQUEL

NICK JOHNSON