2015 Hitter BABIP on Pulled Ground Balls, Part II

Yesterday, I borrowed PITCHf/x data from Baseball Savant to investigate how changes in batted ball velocity affected batting average on balls in play (BABIP) to a hitter’s pull side. If you’re too lazy to click, the short of it is: more velocity coincides with a better batting average. However! Lefties consistently fare worse than righties on ground balls to the pull side at all batted ball velocities.

This phenomenon can perhaps be attributed to the defensive shift. Or to the ease with which second and first basemen can convert singular outs at first base compared to their shortstop and third base counterparts due to the distance (and, thus, difficulty) of the throw. Or, most likely, to both.

But that’s not why I’m here. I’m not in the business to speculate — not today, at least. I’m just here to provide the facts in the form of some numbers I crunched in Microsoft Excel that, if you read yesterday’s post, you will probably find interesting. It has a nifty graph, if words aren’t your thing.

But first, some caveats. (Because, amid a torturous red-eye during which I wrote yesterday’s post, I forgot to mention them. Please accept my apologies.)

• PITCHf/x has play outcomes for balls in play, but not batted ball velocities. Thus, one can calculate an actual batting average on all pulled ground balls but can only infer an expected batting average on a fraction of them. To be exact, approximately 32% of balls in play did not have batted ball velocities associated with them, making expected batting averages even more a guessing game than it already is.
• I use play results from the PITCHf/x as categorized by the following:
  • In play, no out
  • In play, out(s)
  • In play, run(s)

  …which, if you’re cleverer than me, you realized immediately that an in-play out does not guarantee the out was made at first base, nor does an in-play run guarantee an out was not made at first base. Both of these possibilities are real, and neither is accounted for in the calculations.

• Each hitter’s sample size, in terms of pulled ground balls, is pretty small. It’s important, then, to keep in mind the volatility that comes with these calculations and the velocities that influence them as well. (I don’t know for certain how quickly average batted ball velocity stabilizes.)
• Baseball Savant calls David Freese “Dave” and Howie Kendrick “Howard.” We are all now contractually obligated to call them those silly names for the rest of forever.

As you can see, there were (are) legitimate limitations to yesterday’s exercise. I’ll admit it was a matter of laziness on my part. It’s a risk I was willing to take, as I doubt a few stray classifications here at there will inflict wholesale changes to the results. In fact, given the contradictory nature of the two misclassifications, I expect the overall effect to be roughly unchanged — it’s just that changes to individual hitters will take the heat.

Enough chatter.

I don’t expect anyone to understand what’s happening here from one glance, so allow me to explain. Column PGB represents the total number of pulled ground balls in 2015, PGB BA the batting average on such ground balls and PGB xBA the expected batting average based on batted ball velocities and hitter handedness. ΔH indicates the change in total 2015 hits per this information, and ΔBABIP and ΔBA adjust each hitter’s overall BABIP and batting average accordingly. Players shaded in green outperformed what was expected of them by this measure; red, underperformed.

A common theme at the top: Dee Gordon, Jose Altuve, Jarrod Dyson, Starling Marte, Alejandro De Aza, Michael Taylor, Leonys Martin, Jose Reyes, George Springer… the list of fast dudes who racked up a few extra hits than they were expected to goes on and on. And when you look at the bottom of the list and see names such as David Ortiz, Albert Pujols, Prince Fielder, Ryan Howard, Mark Teixeira, etc., it becomes clear that youthful legs are a critical component to any kind of success that deviates from the norm on ground balls to the pull side (after controlling for handedness).

I can only present the data sorted in one particular way, but if you could do yourselves a favor and sort “PGB xBA” in descending order — ah, there. Notice some interesting names here: Giancarlo Stanton, Jose Bautista, Mark Trumbo, yes, yes. But others: Kolten Wong. Mookie Betts. Maikel Franco. Jonathan Schoop. Names among the game’s youth movement and, aside from Betts, names that are, perhaps, underappreciated.

After a monstrous two-thirds of 2014, Wong came up short in 2015, and while it wasn’t a bad season by any means, fantasy owners were left disappointed. His BABIP has slouched throughout his entire, albeit short, major league career, so it wouldn’t be fair, nor wise, to attribute this deficiency to pulled ground balls alone. But the fact that he had the third-best expected batting average — essentially demonstrating he had one of the best batted ball velocities in the game, only two points below Stanton with a sample size twice as large — says a lot about the contact he’s making. He’s only 25 with room to grow.

Franco made silly contact in 2015 and, unlike Wong, his batting average reflected it. But we don’t care about his right-handed pull-side ground balls — we care about that power, that 25-homer power that comes with a batting average that won’t kill. It’s a bad time to be only a good young third baseman with Manny Machado, Nolan Arenado, Todd Frazier, et al. around, but 10th overall at the position ain’t a half-bad price for that kind of production — basically like Kyle Seager, but four rounds later.

Schoop, like Wong, got shafted a bit on pulled ground balls, but his BABIP fared well otherwise, indicating he may have gotten lucky elsewhere. Speaking of hard contact, his power paced out to something like 30 home runs over a full season. Dude makes hard contact, so it’s legit, perhaps more legit than Franco. But that plate discipline… yikes. If you live by Schoop’s sword, be ready to die by Schoop’s sword. In other words, you’re better off in non-weekly leagues where you’re not gambling on his small-sample volatility. But 25 home runs at second base, even with a .250 average? Being drafted 20th at the position, with only Ryan Flaherty as his current competition for the starting gig? Sure, why not.