Starling Marte and the Quest for the Perfect Batted Ball Profile

What follows is a brief excerpt from the latest edition of FanGraphs Audio featuring Kiley McDaniel, and also the approximate moment when I started conducting research for this post and subsequently stopped giving my undivided attention to the aforementioned podcast:

A very literal transcript, for those unable to listen to the embedded audio for whatever reason:

Carson Cistulli: Starling Marte is really — uh, is so good.

Kiley McDaniel: How good is he?! (sarcastically)

CC: Well, he’s good! He also has a strange profile — you’re probably aware of this. But, his plate discipline is still not particularly well-developed. But he probably has, at least, one of the best batted ball profiles of any major leaguer at this point.

KM: I remember when I was in Pittsburgh, the sort of — well, I don’t want to speak for the organization — but the question I was asking is, is he the guy that can walk very little and still, like, has the bat-to-ball skills to make it work? And, y’know, hit .280 with a 4% walk rate or whatever his numbers are. And I watched him in Altoona — he was in Altoona the year I was there — and I thought yes, but I wasn’t willing to bet tens of millions of dollars on him being, like, one of the very few guys that can do that. Yeah, he’s definitely a unique fit.

So now you know where I’m coming from.

What we know about Marte is that he is good. Jeff Sullivan even called him a potential MVP candidate for Fox a couple weeks ago. We know he plays excellent outfield defense, we know he steals a ton of bases, and we know that he’s been well above average at the plate thus far in his career. But to that last point, there’s been some skepticism.

As Kiley alluded to, it’s quite rare for someone with Marte’s plate discipline to experience the type of success he’s had. Marte strikes out more than the league average, walks far less than the league average, and doesn’t possess anything that resembles elite power. Typically, that’s not a recipe for success. But Marte’s recipe is a bit different, in that he’s thrived on the ball in play.

When Marte first came up, he posted a .333 batting average on balls in play. In his first full year, he posted a .363 BABIP. When we see an extreme BABIP, we immediately expect regression to the mean. That’s, like, sabermetrics 101. So our very own Chris Cwik wrote a post after the 2013 season titled, “Starling Marte Trying to Beat BABIP,” and called for regression in 2014. Cwik later felt compelled to issue a public apology when Marte actually boosted the BABIP to .373.

Since Marte’s rookie season, he’s seemingly transitioned from a good hitter to a great hitter. His career BABIP currently rests at .363, which is a top-15 mark all-time, and so the question now becomes: Can Starling Marte really beat BABIP? So far, he’s done it like few others in history.

We know there’s some luck involved with batted balls, but we also know there’s a lot more to it than luck. Hitters with a propensity for line drives are better off, because line drives go for hits more than any other batted ball. Hitters with low pop-up rates are better off, because pop-ups almost never go for hits. And hitters who are fast are better off, because they can beat out grounders which others can’t.

It stands to reason, then, that any hitter who might excel at all three of these things simultaneously — the ball in play trifecta, if you will — could represent the perfect mold of a hitter that we can reasonably expect to sustain a BABIP around or above .350, which is extraordinarily high. You see where I’m going with this.

In 2002, we began collecting batted ball information. From there, I set a minimum of 1,000 plate appearances, which netted me a pool of 656 players. I tossed those players into a spreadsheet, along with their respective line drive rate, pop-up rate, and speed score, and ran some calculations. I calculated league averages, and I calculated standard deviations above or below the mean for each player in each category. I summed the three z-scores for each player, scaled them so that 0 was league average, and called the resulting metric BIP Score, or “Ball In Play Score.”

I found that the r-squared of BIP Score and BABIP was about .52. In other words, a little more than 50% of BABIP can be explained by just line drives, pop-ups, and speed. This is far from a revolutionary finding, and something that’s already been covered in works like xBABIP by Jeff Zimmerman and others. But still, this table of the top 10 BIP Scores was quite pleasing, and it confirms the belief:

BIP Score leaderboard, 2002-Present
Name	PA	LD%	zLD	IFFB%	zIFFB	Spd	zSPD	BABIP	BIP Score
Austin Jackson	3230	23.7%	2.0	2.9%	2.1	6.9	1.8	0.353	2.0
Starling Marte	1293	22.0%	1.0	4.8%	1.6	8.1	2.6	0.363	1.7
Joey Votto	4062	25.3%	2.8	1.5%	2.6	3.5	-0.4	0.355	1.7
Matt Carpenter	1785	25.0%	2.7	2.2%	2.4	4.4	0.2	0.338	1.7
Dexter Fowler	3140	22.6%	1.3	4.5%	1.7	6.7	1.7	0.348	1.6
Michael Bourn	4428	21.1%	0.5	3.4%	2.0	7.9	2.4	0.342	1.6
Alejandro De Aza	2176	24.9%	2.6	7.3%	0.8	6.3	1.4	0.330	1.6
Jason Kipnis	2035	23.2%	1.7	3.9%	1.9	5.9	1.2	0.308	1.6
Matt Kemp	4496	22.4%	1.2	2.9%	2.1	6.0	1.2	0.351	1.5
Freddie Freeman	2616	26.7%	3.6	4.4%	1.7	3.0	-0.7	0.338	1.5

Admittedly, this is far from a perfect metric. I’ve treated line drives, pop-ups and speed as equals, and of course they don’t each have the same influence on BABIP as one another. This wasn’t even about creating a new metric, I just wanted to gain some context with regards to Starling Marte. But it’s something, and it passes the smell test with flying colors. The only guy with a career BABIP below .330 in this table is Jason Kipnis, and he’s someone I’ve already had pegged as a bounceback candidate in 2015, as you can read in my FanGraphs+ player capsule of him.

And up there, second only to Austin Jackson, is our hero. Marte checks in at least one standard deviation above the league average in all three of our selected categories, with speed being his biggest asset. Although Marte excels at all three, that doesn’t necessarily have to be the case. Joey Votto and Freddie Freeman aren’t fast, but avoid the pop-up and hit enough line drives to make up for it. Michael Bourn doesn’t hit many line drives, but his speed and pop-ups do the trick. And Alejandro De Aza doesn’t have an elite pop-up rate, but fares well in the line drive and speed categories.

Not everyone with a high BABIP scores well in BIP Score. Yasiel Puig, for example, owns a career .366 BABIP — higher than Marte’s — but actually has a negative BIP Score, thanks to his low line drive and average pop-up rate. It just so happens that Marte hits on the trifecta and has the BABIP to go along with it.

A different way to visualize Marte’s place:

Should we still expect some regression? Sure. Marte is still something of an outlier among the outliers. And speed peaks early, so we should expect Marte to get slower before we should expect him to get faster. We already figured this was part of Marte’s ability, but here we’ve got numbers to prove it. If there’s any player in baseball equipped to sustain a BABIP above .350, it’s Starling Marte. So far, in his career, all he’s done is hit line drives, avoid the pop up, and run really fast. As long as he keeps doing those things, he’s going to be a good hitter — and more importantly, a very good player — for a long time. Plate disciplined be damned.

If you’re interested in full BIP Score data from 2002-14, it can be found here.