Fun With Arbitrary Statistics

There are a lot of great statistics in baseball these days. They measure everything! Swing path tilt? Contact point against center of mass? Exit velocity? Hard-hit rate on opposite field line drives? You can get a report on any of those things at the wave of a few fingers. Expected wOBA? Barrel rate? There are acronyms and stat blends and projection aggregates for days. It’s analysis paralysis; the hard part isn’t finding stats to describe hitters, but figuring out which ones not to use.

I don’t have a foolproof method for seeing through all the noise for you. But I do have a fun experiment in how to work with statistics in such an overwhelming environment. I want to suggest a method that I call, These Things Are Good. Basically, it boils down to this: Come up with some statistics that you think are good without pre-determining which players you’re looking for, measure how good the entire league is at your statistics in question, and see what shakes out.

How should we do this in practice? I started by saying that I think pulling the ball when you hit it in the air is good. That gives me the first statistic I care about: air pull rate. I turned that into standard deviations for every player in baseball so that we could compare apples to apples across multiple statistics, then started looking for who the standouts were across all categories.

Air pull rate is nice, but it’s certainly not the only statistic that I’m interested in. Next, I wanted guys who hit the ball hard when they put it in the air. After all, exit velocity matters far more when batters can elevate. I did the same thing and put that in z-score terms via standard deviations. If you’re wondering what kinds of hitters these two categories identify, Kyle Schwarber, Griffin Conine, and Junior Caminero are the top three.

I might like power, but I also hate grounders rolled over to the pull side, so my next category was an inverse one: percentage of grounders that aren’t pulled. Schwarber, for example, pulls his grounders at a huge clip, 2.55 standard deviations higher than league average. Now Caminero shows up as the hitter who most exemplifies the skills I’m looking for – tremendous damage in the air, hard to shift against on the ground. Conine and Jorge Barrosa round out the podium among batters with 150 or more plate appearances, for the record.

That covered all the contact quality I was interested in looking at, but I can’t in good conscience come up with a filter for good hitters and ignore plate discipline. In keeping with the statistics I’d picked so far, all of which focus on process instead of results, I added two more process plate discipline statistics. First, I looked at swing rate on pitches over the heart of the plate. Corey Seager is the best hitter in baseball at this particular skill – SEAGER and all. Jeff McNeil and Ozzie Albies are great too. But as an example of why heart swing rate isn’t perfect, consider Ezequiel Tovar. He measures out very well by heart swing percentage – but that’s because he swings at absolutely everything.

Thus, I also added swing rate on pitches nowhere near the plate, in the chase and waste zones. I inverted this one as well; fewer swings at bad pitches is better. Tovar, for example, swings at pitches in the chase and waste zones 2.3 standard deviations more often than league average – abysmal. Seager swings at pitches in the chase and waste zones less than average – masterful.

These five stats were enough for me, so I first set out to see who’s above average in all of them. Bo Naylor and Max Schuemann have accomplished both in tiny samples. Four players have managed it in reasonable playing time: Tim Tawa, Zack Gelof, Tyler Soderstrom, and Matt Olson.

That’s a strange list, and it shows one weakness of this first way of looking at things. If you just ask for a binary yes/no, you’ll get guys who are ever so slightly above average in these skills. But that’s not really the mark of a great player. Great players either do many things at a well-above-average level, or do a lot of things OK and have one standout carrying tool. Tawa, for example, is an eighth of a standard deviation above average for air pull rate, an eighth of a standard deviation above average for air exit velocity, and 0.03 standard deviations above average in bad swing rate (above here being the good way). Technically, he’s above average at everything. But in practice, he’s basically average at everything, and those two things aren’t the same.

Gelof, Soderstrom, and Olson each have things to recommend them. They all lift and pull the ball with force, with better numbers than Tawa there, and they all also have solid plate discipline. But I want my metric to show how good players are at a skill, not just whether they’re above average, so I decided to add up all the standard deviations so that I could account for magnitude.

In doing so, I had to make a decision about how heavily to weight each skill. I don’t think it’s fair to say that each is equally important. Hitting the ball hard, for example, is much more correlated with success than not pulling it on the ground. So I made a few common-sense adjustments to the weightings, like so:

The “Inverted?” column just notes whether higher is better; “No” means a higher z-score is better, “Yes” means that I flipped them before using them. Why these particular weights? Eh, because they make sense to me. But that’s not all that rigorous, so I also checked the correlation between this statistic and wRC+ for various weights of each statistic. This blend is pretty good! It’s the best I could find without just running some kind of solver to maximize r-squared. But these weights explain 25% of the variation in wRC+, which is pretty good, and also double the amount of variation explained by equal weights, so I decided that these are good enough for me.

Here’s a quick rundown of how I picked these weights. I first determined that hitting the ball hard had to be the biggest weight and set that at 2.0. For me, not swinging at bad pitches is second-most important, so I decided that had to be the only other weight above 1.0. I personally favor air-pull guys over tough-to-shift groundball types, so I made that the third-most-important weight, tied with heart swing rate, which also appeals to me. (An initial cut of this had heart swing rate lower. I’m unsure what’s best, and again, this is a very unscientific process.) Finally, not hitting pulled grounders matters, but it doesn’t matter that much unless you’re awful at it, so I gave it the lowest weight.

The best hitter in baseball based on this very specific way of measuring things? That’d be Munetaka Murakami. He does the two skills I find most important – crushing the ball in the air and not swinging at bad pitches – extremely well, and while he’s not great at the other three skills I listed, he’s not killing himself there either:

That table looks lonely, though. Let’s add the next nine players (min. 300 plate appearances here, I was picking minimums somewhat arbitrarily throughout the process):

There are a lot of very good hitters on this list. In fact, it fits the classic rule that a good statistic is 80% stuff you already knew and 20% surprises perfectly; this list is seven 2026 All-Stars, Ronald Acuña Jr., and then two guys who you might not have thought about even once this year.

Plenty of ink has been spilled about Torkelson’s long and winding major league career. Suffice it to say that the skills that made him the first overall draft pick in 2020 are similar to the kinds of skills that get you on this list. I’m more interested in Hernández, though, so the remainder of this article is less about this interesting-yet-fundamentally-unscientific method of finding good players, and more about one of the good players I found.

Hernández has been a player of note since 2020, when he was traded from Texas to Tampa Bay in the Nathaniel Lowe deal. He was a Top 100 Prospect for us at the time, and after a convoluted path through the minors, he debuted for the Marlins in 2025 with a solid season, putting up 1.3 WAR and a 118 wRC+ in 87 games. He scuffled to start the 2026 season and briefly returned to Triple-A, but since returning, he’s played his way into an everyday role. He’s hitting .250/.314/.529 since his May 7 call-up, good for a 126 wRC+, and has been one of the best hitters on the Marlins as they’ve surged back into playoff contention after a rough 12-game skid last month.

It’s not hard to understand why Hernández is succeeding this year. As I’ve already laid out in the premise of this article, he basically does all the things that I like hitters to do: He chases less than average, swings at pitches in the zone more than average, and does plenty of damage when he connects.

You’ll probably notice that I left one key part of hitting out when constructing my formula: Making contact. I did that because I couldn’t think of a great contact number to use, and also because I don’t think it’s particularly correlated to overall success after you’ve already controlled for things like making good swing decisions and hitting the ball hard when you connect. Hernández is a good example of what I mean here. He’s coming up empty fairly often when he offers; Baseball Savant has him in the sixth percentile for whiff rate. But, well, Schwarber is in the fifth percentile for whiff rate. Kurtz is in the first percentile. Plenty of the very good power hitters identified by this method swing and miss a lot; they just take good swings and hit the ball hard when they make contact.

Hernández is well on his way to doing just that. His patience isn’t in question; he posted double-digit walk rates in every year of his minor league career. But when he was striking out 30% of the time in the minors, it was easy to imagine how this might all fail. In 2022, he posted a 31.4% strikeout rate in High-A; that’s not the kind of line that translates well against big league opposition.

As it turns out, though, a change in approach was all he needed. That version of Hernández was too passive; his 42% swing rate was way below big league average, and he posted numbers in that range in 2021 and 2023 as well. Since then, he’s become less selective, chasing more but also getting more high-value swings off. His swing rate climbed to 46% in Triple-A in 2024, 45% in the majors in 2025, and 46% in the majors this year.

There are good and bad ways to increase your swing rate, but Hernández did it the good way. He’s still quite patient outside the zone, but he’s swinging at strikes more often. He’s not making an incredible amount of contact against those strikes – his 78.6% zone contact rate is eight percentage points below average. But he’s swinging enough, and with enough force, that pitchers can’t just chuck it down the middle early in the count and then spam secondaries late.

Another way of thinking about it: You can’t control where pitchers throw you the ball, but you can certainly give them incentives. Hernández’s old combination of low contact and low in-zone swing rates made pitchers’ jobs relatively easy; he wasn’t going to chase, but he probably also wasn’t going to take early swings at pitches in the strike zone. Now, though, the incentives are confusing. He swings more than average at pitches over the heart of the plate, and even if he misses a few, tossing cookies to a guy with 80th-percentile bat speed and a penchant for lifting and pulling is a bad idea. On the other hand, he doesn’t chase a lot, and if he gets ahead in the count, he’ll especially look to do damage. It’s a tough spot for opposing arms.

This isn’t a style of hitting that just anyone can adopt. Hitters with less power on contact would find themselves overwhelmed by a stream of pitches in the strike zone. Hitters without Hernández’s excellent sense of the strike zone would drown in sliders below the zone. But he’s sitting in a happy medium right now; the obvious solutions against him basically aren’t working. Even with his bottom-shelf contact rate, he’s been excellent since returning to the majors, and from my perspective, he might be even better than his results. Neat finding for a very silly, very ad hoc statistic that I think nonetheless captures a lot of the best hitters in baseball – a group that Heriberto Hernández might be a part of.

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