Good Luck, Bad Luck, and Batting Average on Balls in Play

Ryley Delaney
2 years ago
BABIP. What is it? BABIP or Batting Average on Balls In Play is a metric used to measure how often contact leads to a hit. Some say it measures luck and I will agree. To a certain extent that is.
BABIP is a stat that needs further explanation using further stats. Reese McGuire is often considered a lucky hitter. Why? His BABIP is .350.
Now the same people that would consider McGuire lucky wouldn’t consider Vlad Guerrero Jr lucky, even though his BABIP is slightly higher at .352. 
This begs the question, what’s the difference? In this article, I look to answer that through two explanations while also giving an example of an unlucky hitter.

I am (bat) speed

Baseball is quite a complex game even if non-baseball fans will tell you otherwise. Hitting is no different. As a baseball outsider, we can use stats to quantify how good a player is. 
To put it simply, the difference between Vlad Jr and McGuire comes down to the fact that one player hits it hard while the other player hits the ball at medium speed 61% of the time.
Let’s talk about percentiles using Baseball Savant.
Reese McGuire doesn’t hit the ball hard. He’s in the 50th percentile for max exit velocity. In previous seasons, it was in the 33rd percentile in 2018,  the 35th percentile in 2019 and the 14th percentile in 2020. He’s hitting the ball harder than ever before, but simply put, he still doesn’t hit it hard enough to justify a .350 BABIP.
Now we come to Vlad, who has a higher BABIP. We all know Vlad is not a lucky hitter even though we’ve established Reese is. Let’s dig deeper into Vlad’s velocity.
Fast. The question has been answered.
Vlad is in the 99th percentile for average exit velocity, max hit velocity and hard hit%. Vlad’s BABIP is so high because if you’re a defender, you simply have little time to react if a ground ball is not hit directly to you. What’s more is that Vlad is not a flyball hitter. Only 32.8% of the time does Vlad hit a batted ball as a flyball. The rest comes from line drives (21.7%) and ground balls, aka bullets if it hits the defender’s chest (45.5%).

The Shift

Don’t listen to the Jays broadcasters, the shift works incredibly well. I’ve been reading “Big Data Baseball” by Travis Sawchik as of late, which is about how the Pirates finally had a winning season for the first time in 20 years. Not only is it a better version of Moneyball, but it goes to explain that the shift has been around since the start of baseball; however, it rose to prominence in the early 2010s by small market ball clubs such as the Ray, Brewers and Pirates.
So why is this relevant? Well, another explanation as to why McGuire has such a high BABIP is the fact that he can hit against the shift. While he is a pull hitter, 25.6% of balls that he hits go the opposite way. You can even see his approach when he shows bunt, something he is fond of.
When not in the shift, Reese has a .440 average in 26 plate appearances. In every type of shift, he’s hitting .309 in 55 plate appearances. This is largely because of the non-traditional shift, likely the “Ted Williams shift”, which sees three infielders on the pull side. In a traditional shift, he is only hitting .239 in 46 plate appearances. This is low, until you realize that catchers usually aren’t hitting for average.
This is to say that while he is lucky, he has been able to hit against the shift, which in turn has inflated his BABIP.

Unlucky hitters

Now we get to the low end of BABIP, which generally means that hitters have been unlucky depending on the circumstance. In this section, I’ll be discussing Alejandro Kirk’s hitting and why his BABIP tells us he’s been unlucky.
If you follow me on Twitter, you know that I’m a big Kirk guy as we’re both 5’8 and were born in 1998. Not just that, but Kirk has shown the signs of being a fantastic hitter, even in a small sample size.
After getting the call up in 2020, Kirk hit like an utter madman in his 25 plate appearances, owning a 166 wRC+, hitting for a .375 average and striking out only 16% of the time. For 2020, he had a BABIP of .421 and while I think he is a fantastic hitter, this was still lucky. 
However, in 2021, there was no such luck. In his 46 plate appearances in the majors this season, he is hitting .225 with an OBP of .326. His wRC+ is at a respectable 118. Not just that, but he has only struck out 13% of the time while walking 10.9% of the time.
These numbers are all pretty impressive for a guy that’s never played above high A, but what is really impressive is two things. Firstly, he BABIP is only .194, meaning that, unlike Reese, he is very unlucky. However, what’s even more impressive to me is the fact that he sees a wide distribution of pitches and still is able to hit for a respectable average.
In 2020, he was thrown plenty of fastballs as he was new to the league. This season pitchers distributed their pitches fairly evenly and Kirk has still been successful. 
Kirk is in the 64th percentile for Max Exit velocity and while his hard-hit % has dropped from 40% in 2020 to 23.5% this season, Kirk only hits the ball for soft contact 14.7% of the time.
While I could write an entire article on Kirk and why I believe he and Moreno are the catchers of the future, what I’m hoping the reader takes away from this article is that BABIP is not a good stat when it’s on its own. There is a deeper explanation as to why a player gets more hits.
As always, follow me on twitter @Brennan_L_D. I managed to get my first non-reply tweet to nearly 100 likes, so for clout that’s pretty cool I guess.

Check out these posts...