Covering the Front and Back Pages of the Newspaper
September 2, 2003
BASEBALL: Team Defense In Flux
If defense in general and team defensive efficiency in particular is an under-reported phenomenon in baseball (at least, under-accurately reported), then in-season changes in team defensive efficiency is really invisible. Let's see if we can remedy that a little.
On July 7 (about a week before the All-Star break, roughly 86-88 games into the season), I decided to take a look at the Baseball Prospectus numbers for team defensive efficiency (i.e., number of balls in play becoming outs), which update daily. Here's where they stood at that point, leaguewide and by team:
Defensive Efficiency Report -- Updated 07-JUL-03
All stats courtesy of Baseball Prospectus; you can check out the current reports here. Without reprinting those in their entirety, I can see a few major trends:
*The AL as a whole is down from .7102 to .7088 (.7062 for the second half), a rather dramatic falloff in this context.
*Large drops (comparing 1st half to current percentage):
Angels, .7242 to .7147
Orioles .6876 to .6970
I'll admit that I couldn't spot a clear pattern that would tie the shifts to personnel changes in the second half, although obviously some of these teams have changed some starters. It is true that some of the teams showing improvement are out of the pennant race. But the trendlines for a number of teams have shifted, and with them can go their fortunes.
P.S., Hopefully the Prospectus guys will include in-season breakdowns as their premium site brings in more revenue to support the kind of stat sorting that is routine on the bigger sites.