Justin Smoak has had an anomalous year at the plate, at least compared to every other year at the plate he’s had up until this year. There’s been a fair amount of discussion over whether this anomaly will continue to the point of no longer being an anomaly, or whether his performance will at some point revert back to what it was before this year. Most people tend to think it will be somewhere in between, and the differences of opinion have occurred about how in between it will be. Some people say that his BABIP has naturally gone up because he’s hit the ball harder. Other people say that it’s gone up because he’s been lucky. Some have, in fact, stated that it would be anomalous for someone as slow as Justin Smoak to be able to maintain a BABIP as high as .320.
Not having a good internal metric for judging fatness and BABIP, I took this to be likely true until I noticed something the other day: Kendry Morales has a BABIP in the same neighborhood as Justin Smoak. As I write this, Kendry Morales is at .323 and Justin Smoak is at .329. I also realized that Kendry Morales does not have the blazing speed of Chone Figgins or Ichiro that would inflate his BABIP to levels above those attainable by Justin Smoak and other fat people. I wondered if Kendry Morales was having an anomaly year like Justin Smoak, and if so perhaps we should maybe not be as excited about providing him with a qualifying offer. But no, his career average BABIP is .309, and he’s had previous years as high as .329. So breaking the .300 barrier is not something unique among fat people. Then I noticed names like Billy Butler and Miguel Cabrera with BABIP values well above the now pedestrian seeming .329 of Smoak and Morales. Perhaps there was more to this than I had originally thought.
I copied the BABIP values of all qualifying players in 2012 into EXCEL and plotted it against their BsR values. This seemed to be the best measure of non-fatness available. The graph was…nonhelpful. There was no trend. The R2 value was .0116. If you doubled that number, there still would not be a trend. At least the line was sloping in the right direction. But based on this data, there is little reason to think there is correlation between BsR and BABIP.
I thought maybe if I looked at multiple years of data, a trend might show up. Afterall, jumps in BABIP are often associated with reasons for caution about a particular player. So I took data from 2010 to 2012 with a minimum of 1000 plate appearances. Still no trend. The R2 value was .0213, so nearly double what it was before. However, it had increased, so perhaps there was a trend that would emerge as the size of the data sample increased.
Maybe then I should have looked at even more years of data, but this isn’t my job and that sounds like a lot of work. I’ll let someone else do that. The point is, I interpreted some of the discussion around Justin Smoak to mean that fat people don’t have BABIPs that high, that if they ever did it would be a freak event among elite level athletes. The fact is that sometimes they do, and there’s no reason to think that over the course of a year, or even three years, fatness has any correlation at all to BABIP.
Of course this doesn’t mean that his projected BABIP going forward shouldn’t be regressed somewhat from his current value. But realizing that Justin Smoak isn’t a freak of nature for having an ungodly high BABIP of .329 has given me a bit more confidence in his ability to be an average-ish firstbaseman going forward, as opposed to being slightly below average but still playable.
Hopefully this information will be helpful for others who are interested in the statistics of baseball when they read overconfident assertions from supposed experts in the field. Statistics never has worked that way, and it’s not changing because we’re applying it to baseball.