Baseball Crank
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

SEA A32326969325724523.7418
OAK A32777208825929519.7347
ANA A326175510224633512.7242
CHA A32587359127727545.7222
DET A33307959428722405.7220
TBA A340279110634852446.7204
CLE A33848068827439472.7141
MIN A338681610023329547.7109
KCA A34208419730935472.7032
NYA A33488138119727626.6971
BOS A34758379028835612.6951
TOR A347288410926832546.6921
BAL A33248479626143520.6876
TEX A348188811134535557.6806
PHI N32556997726739577.7290
LAN N32116456327022714.7283
ATL N33717507832217555.7199
SLN N348283211928331514.7187
SFN N33767587732323534.7185
MON N338779711326537551.7175
ARI N33947498428542645.7156
PIT N33428029527132466.7147
CHN N33937048034541762.7118
SDN N352781611035840601.7080
MIL N348585312930630567.7049
CIN N351687612134328474.7039
HOU N34277767932845621.7039
NYN N338283210232721468.7037
FLO N34738286929919624.6917
COL N358791610632146525.6871

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
Tigers .7220 to .7109 (like they need another negative trend)
Phillies .7290 to .7205
Dodgers .7282 to .7239 (note that the Dodgers are still leading the NL, but their defense has regressed towards the mean)
Cardinals .7187 to .7126
Expos .7175 to .7117

*Large gains:

Orioles .6876 to .6970
Reds .7039 to .7091
Astros .7039 to .7122 (the most dramatic improvement)
Marlins .6917 to .6986
Rockies .6871 to .6961 (those last two and the Orioles also being regressions towards the mean).

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.

Posted by Baseball Crank at 6:55 AM | Baseball 2002-03 | Comments (0) | TrackBack (0)
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