Friday, January 02, 2015

Tigers Infield Worst in MLB in Preventing Hits On Ground Balls

The Tigers are counting on a healthy Jose Iglesias to improve their infield defense in 2015
(Photo credit: Julian Gonzalez/Detroit Free Press)

Last year, I wrote that the Tigers yielded the worst batting average on ground balls (.276) of any team in the majors in 2013. Whether by design or circumstances, the Tigers made some moves to improve their infield defense heading into the 2014 season.  In this post, I will examine how well that worked out...or how much it didn't.  

The infield reconstruction started in late July, 2013 with the acquisition of acrobatic shortstop Jose Iglesias from the Boston Red Sox and continued last winter when they traded first baseman Prince Fielder to the Rangers for second baseman Ian Kinsler.  The latter deal caused a chain reaction of position shifts.  Miguel Cabrera moved back to first base and rookie Nick Castellanos took over at third base after spending 2013 as a left fielder in Toledo.  

It appeared that their new infield would be good enough give the Bengals an average defense which would save them an estimated five wins in 2014.  As it turned out, Kinsler was one of the best second baseman in baseball, but nothing else went as planned. 

First, Iglesias missed the whole season with stress fractures in his shins and the replacements - Andrew Romine, Eugenio Suarez and company - could not pick up the slack. Moreover, Castellanos was more of a liability than imagined - probably the worst third baseman in MLB.  Cabrera defended well in the first half, but was hobbled by injuries in the second half.  

As a result of these problems, the Tigers once again allowed the worst batting average on ground balls (See Table 1 below). According to the retrosheet databases, there were 2,016 ground balls off the 2014 Tigers staff, 567 of which resulted in hits yielding a batting average of .281.  

Table 1: Batting Average Against On Ground Balls, 2014
Team
BIP
H
BA
OAK
1,976
424
.215
SFN
1,982
434
.219
LAN
2,039
463
.227
PIT
2,205
513
.233
CIN
1,916
455
.237
SEA
1,928
459
.238
BAL
1,981
474
.239
SDN
1,933
465
.241
WAS
1,957
480
.245
SLN
1,999
491
.246
MIL
2,035
500
.246
PHI
2,071
510
.246
CHN
1,949
480
.246
TOR
1,933
479
.248
HOU
2,130
529
.248
BOS
1,998
502
.251
COL
2,215
564
.255
NYA
1,912
488
.255
ARI
2,015
516
.256
CLE
2,014
516
.256
NYN
1,994
512
.257
KCA
1,959
514
.262
ANA
1,833
482
.263
MIN
2,034
544
.267
CHA
2,104
572
.272
ATL
1,852
508
.274
MIA
2,155
594
.276
TEX
1,817
503
.277
TBA
1,729
482
.279
DET
2,016
567
.281
The information used here was obtained free of charge from and is copyrighted by Retrosheet.

The major league batting average on ground balls was .252, so you would expect the average team to allow 508 hits on 2,016 ground balls.  Thus, the Tigers allowed an estimated 59 more hits on ground balls than an average infield given the same number of opportunities.  Since the average failure to convert a batted ball into an out costs about 0.75 runs, the Tigers infield was responsible for an estimated 44 extra runs which translated into four wins.  

The lowest batting average on ground balls was .215 achieved by the Athletics.  In comparison to Oakland, the Tigers allowed 133 extra hits on ground balls which translates into a whopping 100 runs further illustrating the value of a strong infield defense.

One might guess that the Detroit hurler most affected by the porous infield would be Rick Porcello, a rather prolific ground ball pitcher.  However, Porcello surrendered hits at only a .241 rate.  Other pitchers were not so reliant on ground balls, but they were hurt more by high averages - Drew Smyly (.326) and Justin Verlander (.323).  

Why the big difference between Porcello and Smyly/Verlander?  This may have been due to random luck or it could be that Porcello induced weaker contact on grounders than other pitchers.  Unfortunately, data such as speed of batted balls are not yet available to the public. It's interesting to note though that Anibal Sanchez (.233) seemed to be unaffected by the poor defense for a second straight year.  

The Tigers made no moves to improve their infield for 2015, but a healthy Iglesias and Cabrera would help.  It's also important that Castellanos improves somewhat.  It's not likely that he'll ever be good, but hopefully he can become below average rather than horrible.  If the infield can manage to be merely average defensively, they can add four wins.  This might be enough to offset a potential downgrade in the starting rotation if Max Scherzer is not signed.  

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