Do you want to see a market inefficiency -- or to be more precise, a competitive advantage -- disappear in about 15 minutes? Read this outstanding piece by Baseball Prospectus's Andrew Koo about the Athletics' significant, but probably fleeting, edge in roster construction.
It's semi-complicated, and so it's possible that Billy Beane and his co-conspirators were the only ones who figured this out. Essentially, the idea is that ... well, here's Koo:
"The Book: Playing the Percentages in Baseball" devotes a chapter to platoon effects. Five pages discuss handedness, a mainstay of baseball analysis today. Two pages cover a less visible effect: batted-ball tendencies. Authors Tango, Litchman, and Dolphin found that fly-ball hitters had an advantage over ground-ball hitters, simply because they are better hitters—you can't homer on grounders, after all. They also found that fly-ball hitters are especially good against ground-ball pitchers, because the former tend to swing under the ball while the latter want the hitter to swing over the ball.
However, Tango et al. noted that this platoon advantage is hard to exploit because players tend to be neutral rather than lean to either extreme. Also, the advantage itself is very small, and hence overshadowed by the handedness platoon. Such a minimal advantage would (theoretically) require being multiplied through several hitters to become meaningful.
So what happens when a determined, resourceful general manager decides to overhaul his lineup with fly-ball hitters, capitalizing on a league-wide trend toward ground-ball pitchers?
Well, now we know. In 2013, 60 percent of Oakland's plate appearances went to fly-ball hitters ... which was the highest figure in the last nine seasons by nearly 18 percent. Or nearly 50 percent, depending on your perspective; the second-highest figure was 42 percent, by the 2010 Diamondbacks.
Granted, the advantage for fly-ball hitters is small, and seems worth worrying about only when a) there are plenty of ground-ball pitchers, and b) the traditional platoon advantage remains well-respected. Well, these days there are plenty of ground-ball pitchers in the majors and the A's have three switch-hitters and they platoon where they can; last season the A's featured only four every-day players (and two of those batted both ways).
In 2010 and '11, the A's finished 11th and 12th in the American League in scoring. In 2012 and '13, they finished 1st and 2nd. Most of this improvement was due to flat-out better hitters. But I'm guessing that two or three slots of improvement were due to the A's exploiting this small-but-worthwhile market inefficiency.
That should still be there next season, as the rosters are mostly set. But it's going to disappear within two or three years, as all the other teams that read internet columns place slightly higher values on fly-ball hitters.
First Moneyball and now this. Man, it's not easy being Beane.