Monday, April 30, 2012

Team Defense Hurting Tigers

The Tigers have allowed 4.7 runs per game, which is the fourth highest total in the American League this April.  The first inclination is to blame the pitchers, but is it all their fault?  One of the main reasons the Tigers have allowed so many runs is that they have a .318 Batting Average on Balls in Play (BABIP), the second highest in the league.  The BABIP statistic can be confusing though because when you see a high batting average against a pitcher, it looks like the pitcher pitched poorly, which is not always the case.

Another way of stating the above is that about 32% of the balls in play with Tigers pitchers on the mound have fallen safely for hits and 68% have been converted into outs. The league medians are about 28.5% and 71.5%.  So, the Tigers are about 3.5% worse than the median team at converting batted balls into outs.  why are the Tigers so poor at converting batted balls into outs?  Is it the famous bad luck of BABIP?  It could be that but there are other possible reasons too.

One explanation for a high percentage of balls in play dropping for hits might be that the pitchers are getting hit hard.  If we look at the batted ball statistics at FanGraphs, we can get an idea of how hard.  About 20% of the balls in play against the Tigers have been line drives which is the third lowest total in the league.  Additionally, 13% have been infield flies, the third highest percentage.  So they have allowed few of the worst kind of batted balls and a lot of the best kind of batted balls for the pitching team.

The ground ball rate of the Tigers staff is 44% which is close to league median.  When they do allow fly balls, about 10.5% are hit for home runs, which is again near league average.  All of the above batted ball data suggest that the pitchers are not being hit especially hard.  

Another reason for a high number of balls dropping for hits might be poor defense.  Looking at three of the most popular advances fielding metrics, the tigers rank at the bottom of the league on all of them:

Total Zone -22
Defensive Runs Saves -19
Ultimate Zone Rating -12

The average of these three numbers is around -18.  So, we would estimate that the Tigers fielders have cost them 18 more runs than what would be expected of an average team.  It's a bit early to trust the precision of defensive stats, but the fact that they are last on all three is telling.  It's not particularly surprising if you've seen most of their games either.

The Tigers ERA of 4.27 is 10th in the league, but  that doesn't account for fielders not making plays.  If we look at statistics which only include what a pitcher can control without the help of fielders (strikeouts, walks, hit batsmen, homers, batted ball percentages) we might get a better sense of how the pitchers are doing:

FIP 4.08 (8th)
xFIP 4.08 (7th)
SIERA 3.80  (6th)

So, the Tigers pitchers now look more middle of the pack than bottom of the pack.  Just looking at the starters it gets even better:

FIP 3.98 (6th)
xFIP 3.78 (4th)
SIERA 3.71 (4th)

So, the the starters appear to be doing pretty well as a group.  The bigger problem appears to be the defense.  Max Scherzer's stratospheric .442 BABIP is sure to drop, but the Tigers fielders as currently aligned appear to be hurting the staff quite a bit.

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