One statistic that gets thrown around a lot as a measure of luck is Batting Average on Balls In Play, or BABIP. BABIP measures how often balls that are batted into the field of play go for hits. Because about 30% of balls in play tend to go for hits, a player with a BABIP that deviates from that norm is viewed as having been impacted by luck. However, as detractors of BABIP frequently note, a player who hits the ball harder is more likely to get hits when putting the ball in play than someone who makes softer contact. Therefore, xBABIP was created, which measures a player’s expected BABIP based on the type of contact that he has made. The gap between xBABIP and BABIP can then be attributed to luck (with “luck” including the impact of ball placement and defense).
I compiled the xBABIP and BABIP data for the key members of the 2011 Yankees, and you can find the numbers below, going from unluckiest to luckiest. The data on hitters comes from an excellent spreadsheet at THT, which notes that the numbers on Yankees players need to be taken with a grain of salt due to the lack of sufficient data on the new ballpark. I have also added career BABIP to the list to provide some context, as hitters tend to have individualized BABIP baselines.
As you can see, a large number of Yankee hitters were unlucky last season. Significantly, Derek Jeter was hampered greatly by poor luck, and as the last column shows, would have been expected to hit .299/.366/.398 with neutral luck, rather than the .270/.340/.370 he actually notched. Those numbers would have been right in line with his 2008 statistics and suggest that he might be experiencing a slow decline rather than the precipitous drop indicated by his actual 2010 line. Similarly, Andruw Jones, Jorge Posada, Russell Martin, Curtis Granderson, Mark Teixeira, and Alex Rodriguez all experienced a significant amount of poor luck on balls in play, and the adjusted lines are likely to alter the perception of their 2010 seasons as well as bode well for future performance.
On the flip side, Robinson Cano benefited from a moderate amount of good luck in 2010, while Nick Swisher was one of the luckiest players in baseball. After adjustment, Swisher would still rate as an above average player, but he may need to switch back to his more patient approach from 2009 if his luck reverses itself in 2011.
I compiled the pitcher data myself, using the formula provided in this Fangraphs post (h/t @Stephen_MR). The data is not adjusted like the hitter data is, but should be accurate enough for rough analysis. Again, I included career BABIP, but note that pitchers tend to have less control over their BABIP than hitters.
Two controversial Yankees were extremely unlucky in 2010, as Joba Chamberlain and A.J. Burnett both were bitten by the Luck Dragon during their tumultuous seasons. Joba’s peripherals suggest that he was actually one of the better relievers in the sport, and these numbers further confirm that bad luck, not bad pitching, hurt Chamberlain in 2010. As for Burnett, this is just another bit of evidence that points to 2010 being an outlier season for him.
As for lucky pitchers, two of the contenders for the final rotation spots, Sergio Mitre and Freddy Garcia, had good fortune last season. Mitre in particular seemed to have a good year in 2010, but his numbers were largely illusory. Finally, two star relievers with traditionally low BABIP’s had extremely good fortune, as Mariano Rivera and Rafael Soriano both had BABIP’s that were far lower than both their 2010 xBABIP’s and their career marks. It will be interesting to see whether they suffer a significant hit in performance if the Luck Dragon comes for them in 2011.
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4 Responses to Do You Feel Lucky….Swisher?
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Prompted by @Stephen_MR on twitter, I’d like to add that looking prospectively, you can assume an xBABIP of .300 for the pitchers in 2011. You can’t do the same for hitters, as career BABIP does factor in for them.
Let me preface my comment by saying I am not a big fan of BABIP. With that disclaimer noted, I would point out that Mariano has consisently outperformed his expected BABIP, so at some point you have to attribute that to skill instead of luck. In other words, Rivera’s only good fortune is his amazing talent.
Agreed, which is why I included his career BABIP as well. I’d argue that he was well below that as well, such that he was likely the beneficiary of at least some good luck in 2010.
I would have hated to see an “unlucky” Mitre. :)