After five consecutive years of BABIPs over .300 for Mark Teixeira, it was reasonable to write off his .268 babip in 2010 as an aberration. We see fluctuations in batting average on balls in play all the time, so 2010 seemed like just another example. Then 2011 happened. Currently posting a paltry .234, Teixeira has defied expectations. Unfortunately, we do not have the power right now to determine the cause.
Baseball Info Solutions (BIS) data available at Fangraphs does suggest a slight shift in batted ball profile; in the past few years, Teixeira has steadily increased his flyball percentage. Of these flyballs, his pop-up rate has been higher than previous levels. Given that flyballs go for hits less often than line drives and ground balls, hitting more typically corresponds with decrease in BABIP. However, given the uncertainty surrounding the precision of batted ball info, slight changes in the data are not all that dependable.
Another possibility is that his plate discipline has declined, driving Teixeira to chase pitches and make weaker contact than before. This theory is also supported by BIS data: In the past two years Teixeira has posted O-swing (the percentage of swing on pitches outside the zone) rates that are much higher than previous norms. But just like before, we need to exercise caution. The league average O-swing has increased dramatically in the past few years. If we verify these rates using PITCHf/x data, we find nearly identical O-swing rates. Additionally, given that his walk and strikeout rates have stayed strong, the possibility that plate discipline is causing his reduced BABIP seems remote.
It seems then that we can not definitely give a why. But what we can do is look at how.
This graph shows BABIP by horizontal location, split up by Teixeira’s handedness; the left side is for when he bats left-handed, and the right side is when he bats right-handed. The graph also is split up by time period—2008-2009 and 2010-2011. Of course these time frames are arbitrary, but they do help to contrast his recent BABP performance with his previous levels. The data shown here are within a rough approximation of the strike zone. Gray bands indicate confidence. The sample sizes are not huge here so we have reason to tread cautiously.
As you can see, there’s not much of anything of note with his performance as a right-handed batter. Indeed, in 2010 and 2011 his BABIP as a right-handed batter has stayed above .290, which is pretty close to his career average once we account for the lower run environment in recent years. His performance as a left-handed batter is where things get interesting. As shown in the graph, there is no significant difference in his BABIP on pitches inside and down the middle. But with pitches on the outer half the plate [-1, 0], there is a clear dropoff.
Were his BABIP decline in 2010-2011 completely the product of luck, we would expect to see it randomly distributed across his performance, not only on pitches that are outside. Of course that is only what we would expect; this does still not preclude the possibility that the difference in his BABIP is entirely due to luck, it just makes it seem less likely. The disparity is very stark; in 2010-2011, his BABIP on outside pitches is below .200, but in 2008-2009 his BBIP is around .300. We also see a difference when looking at the frequency of him pulling the baseball on outside pitches:
This image shows the angle of Teixeira’s batted balls by horizontal pitch location. This is only for his left-handed at-bats. The two dotted lines indicate the horizontal borders of the strike zone for a typical lefty. As expected, he pulls pitches most of the time.
Of note here is that in 2010-2011 he does seem to be pulling outside pitches much more often than before. This may suggest that he has been rolling over on outside pitches more frequently in 2010-2011 than in 2008-2009, though I wouldn’t necessarily categorize this as strong evidence for a change in approach. The graph also suggests that he is pulling inside pitches more often than before, which is surprising.
Has Teixeira’s swing as a left-handed batter changed such that his BABIP performance on outside pitches suffers? As shown above, the results appear to suggest that a change has occurred, but the answer to this question is one that could be better approached by a scout.
References & Resources
*PITCHf/x data from MLBAM via Darrel Zimmerman’s pbp2 database and scripts by Joseph Adler/Mike Fast/Darrel Zimmerman