There was one relief pitcher whom former Mariners designated hitter Edgar Martinez really loved facing. In the 23 times he faced him, he recorded 11 hits (three doubles and two home runs) and four walks, for a slash line of .579/.652/1.053. What wretched quad-A filler guy did Martinez light up like this? Some guy named Mariano Rivera.

The batter-versus-pitcher matchup numbers are a staple of baseball broadcasts, and like a staple, they hurt when they’ve been driven into your head over and over. I think that at this point, it’s well understood that the fact that Smith is 2-for-4 lifetime against Jones does not mean that there’s a 50 percent chance of Smith getting a hit in his next at-bat against Jones. We don’t have the sample size to justify any conclusion at all on whether Smith has some special insight on Jones (or Jones on Smith). He might, but statistically, we need to say “Sorry, can’t help you either way.”

While an individual batter-pitcher matchup isn’t likely to produce enough of a sample to make any sort of meaningful inferences, there’s a school of thought that says maybe we could somehow cluster pitchers together. We can look at Smith’s performance against these 20 pitchers who share some meaningful characteristic to see how he has performed. This is essentially what we do with splits. We just assume that because Smith is a lefty, he is at some disadvantage against this particular lefty. That’s at once silly and likely true. We know that platoon effects persist over time, and we know that dividing pitchers into lefties and righties is easy (hi there, Pat Venditte!) and gives us big enough buckets that we can say meaningful things. But there’s probably more to it than just the geometry of left/right and much more that we need to account for.

Beyond just the platoon effect, how can we cluster pitchers (or batters, for that matter) together in a way that makes sense and where we could take “Smith is 2-for-4 lifetime against Jones” from fun fact to actually meaningful information? There’s been some amount of work around how different hitters fare against different pitch types. For example, there are stats on how well different hitters have fared against fastballs (vs. curves vs. changeups). If he’s done well against fastballs, then maybe teams should shy away from throwing him heat. PITCHf/x makes finding those sorts of splits a matter of few clicks on Brooks Baseball.

I’d like to suggest a different way of thinking about the problem. It’s mostly theoretical at this point, but all the good stuff starts out theoretical.

Decoding the Book
Hitting a baseball is consistently ranked as one of the hardest things to do in all of professional sports. It’s not really all that shocking. A major-league bat must be (by rule) less than three inches in diameter in the barrel. That’s the entire amount of real estate that a hitter has to work with in making contact. Any sort of contact. Let’s not even get into good contact. Not only that, he’s facing off against a ball that is traveling faster than your average highway speed limit and that might take a weird left turn if the pitcher does it right. Yet hitting is the basic unit of a baseball game. Sure, sinking a jump shot or throwing a good pass are each hard enough to do, but the person trying to do them has the ball in his hands when he’s doing it.

Then again, Giancarlo Stanton occasionally does this, so it can’t be that hard.

I would point to another skill that human beings possess that is perhaps even more improbable. Right now, you are looking at squiggly marks on the screen. Somehow, your visual system matches them to culturally agreed values (letters) and wonder of wonders, you can string a few of them together and apply an arcane and Byzantine series of rules for how these letters are used (since I am writing in English) to form words, and then that information is shipped over to the area that processes meanings so that when you see the word “ball,” the area of the brain that deals in spheroid objects lights up. You are further able to string several of these words together and apply even more arcane and Byzantine rules of grammar (gotta love English!) to figure out what a sentence means, and then knit several of those together into some abstract idea. In other words, you are reading.

Reading is a tremendously complex thing. It involves multiple systems across the brain… and my 5-year-old daughter can do it. Not only that, but most people can read and based on the words produce a motor response, which involves a trip through a whole bunch of other subsystems in the brain. Not bad.

We do know that there are people who suffer from dyslexia, a condition where they have persistent troubles with reading, which are the result of some neurocognitive problem (and not because of laziness or stupidity). The term dyslexia itself makes it sound so deceptively simple. It isn’t. In a past life, I used to conduct neuropsychological evaluations for kids who were suspected of having some sort of learning disorder (including dyslexia). In a case like that, the goal is to find the specific skill, or the specific step in the process where language processing is breaking down. There are several candidates. Is this a visual acuity problem? (Prescription: Kid might need glasses.) Is this a fluency problem? (Prescription: Kid can do the work with a bit more time.) Is there a problem in symbolic decoding? (Prescription: Harder to fix, but at least we know where to focus our efforts.) You have to understand the entirety of how the brain processes information in order to understand how to help.

I’d propose that it’s this understanding of information processing is what’s missing from the batter-pitcher matchup question. Batters are, in some sense anyway, reading the pitch as it comes toward them and trying to figure out what to do, and they’re doing it within a few tenths of a second. They’re even successful sometimes.

The Cliff’s Notes Version

The batter’s job is to figure out where (and when) the ball will arrive in the general area of the plate and then decide whether or not it’s a good idea to swing. He can do this in a couple of different ways.

1) He can try to figure it out beforehand. Pitchers are humans and can fall into patterns. Of course, teams run dossiers on pitcher tendencies. The pitcher may also have a “tell” as to what he’s doing. Skill required: Poker skills, especially noticing potentially very subtle changes in behavior. Or being able to browse Brooks Baseball.

2) He can try to pick it out from the pitcher’s release point. Some pitchers have the nasty habit of throwing a fastball from one spot and a curve from another. Not in the sense that their release point wanders as they get more tired, but that the arm action for each of the pitches is distinctly different. He might also try to pick up the grip out of the hand. Pitchers, of course, know this and try to maintain consistent and deceptive mechanics to hide the ball as long as he can. Skill required: High speed visual acuity.

3) The batter can try to “read” the spin or the break of the ball and extrapolate where it’s going. Pitchers, of course, try to get their balls to break “late” so that the batter doesn’t have time to react. Skill required: Visual spatial processing.

4) The batter can try to compensate with either quick cognitive reaction times and/or quick hands/wrists to try to make adjustments with the swing in progress. This is one reason why velocity is nice for a pitcher, because it shortens the time that the batter has to think. Skill required: Quick reaction times, fine motor control

This is massively over-simplifying things, but you can see that a hitter might be particularly good at one of those skills and not so good at another. Those skills are all handled in different areas of the brain. Of course, those areas all work together, but the brain isn’t a single entity. It is a connected bunch of subsystems, some of which are better developed than others. Our batter might be very good at reading the spin of the ball in flight, but if a pitcher is particularly deceptive in his mechanics and doesn’t give him much of a chance to see the spin until it’s too late, then the batter’s superpower is negated. On the other hand, he might be facing a guy who relies on movement—and maybe in the raw sense, has better movement than the first guy—but our batter is good at reading that, so the movement doesn’t bother him as much. Now imagine our batter is facing a guy who throws 98 mph. Now the challenge for him is whether his magic tricks work at speed. If a hitter is at the MLB level, it’s likely that he has at least some ability on each of these skills, and compared to the general population, probably above-average talent, but baseball is a game of small advantages. I think that the more we understand the contours of these small advantages, the better we will begin to understand the chess match that goes on between the batter and pitcher.

Magnus Carlsen?
I’m rather smitten with the game of chess and have been for about the past year. Now, mind you, I’m an awful player. I didn’t play when I was younger, and I usually lose to the computer on easy mode with liberal use of the takeback button, but I find the culture of the game fascinating. At the highest levels, the players all study each other. Prior to the recently finished World Championship of Chess, contested between challenger (and former World Champion) Vishy Anand and current World Champion Magnus Carlsen, Anand took a couple weeks off from competitive tournaments to specifically study Carlsen. How does he make his decisions? What are his patterns? How can they be exploited? (Apparently, it didn’t work. Carlsen retained his World Championship.) Grandmasters will often execute elaborate plans constructed with the hopes that by the time the game nears its end, they will have one more pawn on the board than their opponent.

I find chess to be a good metaphor for thinking about the mental game that goes on in an at bat. Hitters and pitchers study each other. They probe each other for even small weaknesses. One pitch affects the next. Similar to the fact that not all chess players have the same strengths and weaknesses as each other, not all batters and pitchers are equally handicapped. It’s a rather complex set of variables.

What I find interesting about this topic is how little is out there (I suppose that the disclaimative adverb “publicly” is probably a good idea here). The batter-pitcher matchup, more than anything else, is the atomic unit of baseball. It’s one of those things that I always figured that someone would get around to, maybe even me. No time like the present! Thankfully, I’m not starting from scratch. There are plenty of scouting reports on individual players and their strengths and weaknesses at bat. There have been some studies of pitch sequencing, but there’s never been a grand unifying theory of the whole matter. Maybe that’s too ambitious, but there’s not a lot to even try to duct tape one together right now.

So that’s my goal. I will (hopefully) be returning to this topic frequently to try to figure it all out. How does one pitch affect the next? Are there better ways to group players? And taking it to the next level, if we find that we can measure a hitter’s strengths or weaknesses, can we turn that into actionable intelligence? Can we quantify pitch-calling? I probably won’t be able to solve the whole equation, but maybe along the way, we’ll all learn something interesting. This book is still being written.

Thank you for reading

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I've always felt that broadcasters place too much emphasis on Batter vs Pitcher matchups despite sample sizes being too small. What does occur to me after reading your article is that maybe we could use this data to split batters beyond lefty/righty matchups but maybe vs different types of pitching (i.e. fastballers, curveballers, etc). It would be interesting to see how this mentality could be used to build lineups vs pitchers like Kershaw or Bumgarner, for example, or how a pitching coach would suggest a pitcher should attack a lineup filled with curveball hitting batters.
This is an ambitious project. As a subscriber, I encourage you to pursue the research. I would love to see better understand the sparring between the batter and pitcher, and what is or is not important.

The unifying theory in physics is not yet a reality but think of the strides that have been made in the past decades. Certainly, this is not as earth-shattering. But at worst, it should help fine-tune what questions should be asked,

Go for it.
I make a game out of trying to imagine what pitch/location is coming next. More than anyone else, listening to Steve Stone taught me how pitchers set up hitters, when to throw low and outside, when to take him up the ladder, when to cross him up, when to show the fastball inside, and so on. With detailed pitch data, it should be possible to run simulations on how pitch selection and sequence matters.

I'm not perfect at it, but I'm getting better, and it's a thrill to predict a pitch and get it right. One theory I have is that pitches in the middle of the plate but too low or too high are more effective at getting a swing and miss that nibbling at the corners, which a batter is more likely to foul off. i would be interesting to see if you could prove this statistically.
Russell, I really enjoy your approach to understanding cause and effect in baseball. Your perspective is very enlightening. Thank you.