Another Way Robot Umps Would Help

Jon Roegele is the leading authority on strike-zone changes, and I recommend you read his midseason update of the strike zone that was published at The Hardball Times yesterday.

There are a number of interesting findings and developments in the piece, but the headline is that the strike zone is contracting for a second consecutive season after it shrunk for the first time in the PITCHf/x era last season.

In 2015, the strike zone measured 475 square inches, according to Roegele, and 50 square inches in the area 21 inches above the ground and down (i.e. the bottom of the zone and below). It declined to 474 and 45 inches, respectively, last season, and to 464 and 43 square inches to date this season.

A smaller strike zone likely has played some role in the run-scoring surge of the last 48 months, and a smaller strike zone figures to have all sorts of consequences.

Interestingly, despite the strike zone having shrunk last season and having continued to contract this season, the number of pitches in the lower portion of the strike zone and below have increased this season (30.5%) from 30.0% in 2016 and 29.8% in 2015. And it’s not just more breaking balls and changeups being thrown for chases below the zone; the percentage of fastballs thrown down is slightly up this season (19.4%) compared to 2015 (19.1%), according to data provided by Baseball Savant’s detailed zones.

Pitchers are throwing down more often even as the strike zone shrinks, even as batters have become more skilled at driving the low pitch. This suggests that it’s not so easy to change, that pitchers have been conditioned and programmed to target that area. (Or that not enough pitchers are browsing pitch-location data during their idle time.)

It makes sense to think of the power spike in baseball as a uniform change, but that spike has actually occurred in certain parts of the strike zone more prominently than others.

Consider, for example, this chart of the league’s isolated slugging by zone in 2008:

And then the same thing for 2017:

A decade later, the ISO mark in the top left of the zone has actually decreased by a single point, from .183 to .182. The areas middle and low, however, have increased by 30 points in most cases. That speaks to a fundamental change not just in overall power, but specific approach, from batters.

One significant implication of an evolving strike zone — of an inconsistent zone — that perhaps hasn’t received as much attention is the preparation aspect from both the perspective of the individual player and the club. How do you go about planning and preparing as a player when you don’t know how the strike zone will play in a given year? How do you go about building a team as a member of a front office if you don’t know how large the strike zone will be and where the biases will be located?

For instance, entering the 2016 season, if you were a decision-maker for a club, you might want to consider — perhaps you ought to have attempted — to take advantage of a strike zone that had grown every year in the PITCHf/x era, and grown in a particular place: in the lower regions of the strike zone and below it.

Perhaps you invest heavily in two-seam, sinking-fastball pitchers and target an elite pitch-framing catcher, as it’s that lower part of the strike zone where most of the value of framing resides. Perhaps you place more focus and emphasis on having your pitchers target the lower part of the strike zone from the top to bottom of your system.

And what if, after doing all that, the lower part of the zone suddenly begins to dry up?

Earlier this season, I asked Milwaukee reliever Jared Hughes, who has relied on peppering his sinker down in the zone throughout his career, about how he is adapting in an era when the strike zone is contracting, at a time when batters have become more proficient at driving the lower pitch.

Said Hughes:

“If your swing is geared to the lower pitch there might be something else there you can’t get to. In my opinion, every swing, every approach, there is a way to get a hitter out,” Hughes said. “The thing is if I can find a way to have a strength up. To find something to go to up there if I think i need, which I think I do.”

Hughes is trying to evolve, though he’s doing so more through pitch type than location.

He’s evolving on the fly successfully. Among relievers who have thrown at least 100 sliders, he has the game’s top swing-and-miss rate, and for his career he gets about as many whiffs per swing as Chris Sale via the pitch. Hughes’ sinker was so good, he was perhaps under-utilizing his slider. After being released by the Pirates this spring, Hughes has a 2.92 ERA and 3.68 FIP for the Brewers.

Of course, not every player can adjust so quickly.

And if a team has invested too heavily in a strategy to take advantage of soon-to-be-defunct trend, making a change at an organization-wide level can be akin to turning around an aircraft carrier.

Another interesting finding from Roegele is that the gulf between the size of the zone between left-handed and right-handed hitters continues to grow. Wrote Roegele:

The lack of sustained strike calling on the inside part of the plate to left-handed hitters appears to be the most obvious area remaining where the league could stand to improve in steering its strike zone toward the rulebook definition.

In 2012, right-handed hitters posted a superior isolated-slugging mark (.152) compared to lefties (.149), and the strikeout rates were nearly even (19.7% for righties an 19.9% for lefties). To date in 2017, lefties have an advantage both in isolated power (.174 to .168) and in strikeout rate (20.6% to 22.2%).

If you’re employed in a front office, it would seem to make some sense to place an even greater value on left-handed hitters, if this trend continues, if lefties continue to enjoy a more favorable strike zone.

Fans clamor for robot umps when calls go against their clubs. But perhaps more teams and more players will be calling for robot umps for the sake of consistency, for the purposes of planning. While robot umps might not call a perfect zone, particularly at its northern and southern boundaries, robot umps could — eventually — provide a more consistent one.





A Cleveland native, FanGraphs writer Travis Sawchik is the author of the New York Times bestselling book, Big Data Baseball. He also contributes to The Athletic Cleveland, and has written for the Pittsburgh Tribune-Review, among other outlets. Follow him on Twitter @Travis_Sawchik.

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drewsylvaniamember
4 years ago

This is great, and an eye opener for me. I do have a couple of questions:

1) .ISO for high, middle-of-the-zone pitches increased from 2008 to 2017 by 22 points. Is that noise, or an indication that hitters are not merely targeting low in the zone?

2) “474 and 45 inches” to “464 and 43 inches” seems like a huge change. Is there any sense that this might be an intentional shrinking of the zone by umps, perhaps by order of MLB? (I mean, I doubt umps would lengthen games on purpose!)

drewsylvaniamember
4 years ago
Reply to  drewsylvania

Also, I’ve always wanted a consistent zone. I think we could all live with that.

John
4 years ago
Reply to  drewsylvania

I think there are people out there, myself included, who “could live with it” but given the choice, want nothing to do with a roboump. And Travis, I take you’re point, but I find myself unsympathetic to the player who is so specialized, or the organization that is so rigid, that they need to design out a critical part of the game in order extract the most value. This is not like a revision to the slide rule (that makes plays safer and, near as I can tell, changes the game little or not at all); we’re talking about radical change…for what exactly? I’ve seen commenters here argue (and I don’t want to leap too far off the philosophical cliff) that it’s important to GET IT RIGHT because TRUTH IS IMPORTANT or some version of that, but I can’t help but think that’s bogus. This is a children’s game for fun an entertainment, isn’t it? This is not the tax code. This is not medical research.

If this rule change is inevitable and you’re trying to sell it, fine, but if we’re trying to talk about if it’s actually a good idea, if it’s actually needed, if anyone actually *wants* it, I remain unconvinced.

Scientialmember
4 years ago
Reply to  John

The game is worth billions because many individuals enjoy the performance of the athletes and the outcomes for their teams.

The fans want to see the contest between Harper and Kershaw according to the rules of the game. If the outcome of that contest is determined by Joe West instead of the preternatural talents of the major league players, the contest loses its legitimacy. The less that happens, the better.

John
4 years ago
Reply to  Sciential

But, as has been established, on this website and elsewhere, the strike zone is negotiated by the pitcher, catcher, hitter and umpire, and that this is a skill, a part of the game, just like sliding, fielding grounders, hitting for high average, whatever. I don’t see how legitimacy is lost. Getting an out call wrong that breaks up a no hitter, that’s terrible and was rightly designed out of the game.

And it’s not obvious to me, as you seem to imply, that this is what all fans what to see. It’s also not obvious to me that players want it too. Certainly some have spoken out, but I have not seen it reported that there is a crisis here that needs immediate or radical attention. Has a petition circulated? Has this come up in labor negotiations? Who *actually* cares? And how many of them are there? Maybe absurd questions here, and absurd questions now, but this needs serious thought.

In general, I take your point, but what I’m resisting is the assumption that all fans want this, or that it objectively improves the game. These statements are simply not true. Do some people want it and do they have good reasons? Sure, of course they do. But acting like this is a closed case will increase the risk of doing something that hasn’t been thought through and with consequences that aren’t known.

Scientialmember
4 years ago
Reply to  John

Fair points, all.

I don’t mean to speak for all fans; I doubt a plebiscite for robot umps would prevail so no doubt not every fan wants them. I do think Sabemetric fans would easily vote in robot umps, though.

Although command and pitch-framing are certainly skills, I would vastly prefer that the outcomes of plate appearances be determined by Clayton Kershaw’s ability to throw a ball and Bryce Harper’s ability to swing a bat than Yasmani Grandal’s ability to influence Angel Hernandez’s perception by the way he keeps his glove still.

I get that some people respect the tradition and human element. But the original game didn’t even have balls and strikes. It was intended to be a contest to see if the defenders could retire a batter on a ball in play. Umpire-called balls and strikes were a solution to a problem, a necessary evil, to give an incentive to the pitcher to deliver hittable balls and for the batter to strike at them. For nearly 140 years, we had no better option to solve this problem innate to competitive baseball than to pay Tim McClelland to slowly raise his hand when he thinks a pitch went over the plate. But now it’s clear the robots can do better, and I, for just one, cannot wait.

kenai kings
4 years ago
Reply to  Sciential

Woe… the original game? So, are you refering to rounders or peg-ball or maybe stoop-ball? The game, as played at Hoboken by the Knickerbockers, aloud the batter/hitter to request a high or low ball and there were strikes.

kenai kings
4 years ago
Reply to  kenai kings

upon further research…
the Massachusetts Game had the strike calls in case of delayed game tactics.
the high and low pitch requests were not implimented until some few years later.

John Autin
4 years ago
Reply to  John

Step back and ask if you want a game where the strike zone is “negotiated” by anyone. And if you do like that, why not push for other decisions to be similarly “negotiated”?

I want the rulebook strike zone called as much as possible. I’m 54 years old and a lifelong baseball fan who respects tradition. But I have never once enjoyed the “art” of stealing strikes, and I have zero attachment to human umpires.

david k
4 years ago
Reply to  John

Ok, if you think it’s ok to get rid of calls at 1B that rob a pitcher of a no-hitter (or a perfect game in Gallaraga’s case), why not get rid of calls at home plate that can do exactly the same thing? Balls and strikes can clearly affect a perfect game on a bad ball four call, not to mention screwing up an entire AB on ANY call.
Fans complain all the time about bad calls, especially balls and strikes. Do you think that should continue because it’s “interesting” to have drama and controversy? I’d rather drama and controversy come from the game itself and not from incompetent umps.

rounders
4 years ago
Reply to  Sciential

Joe West is the reason robots are definitely coming.

johansantana17
4 years ago
Reply to  drewsylvania

MLB instructed umpires to stop calling so many low strikes before the season began.

https://www.si.com/mlb/2017/02/13/raising-strike-zone-pace-action

drewsylvaniamember
4 years ago
Reply to  johansantana17

Thanks. Definitely a shrinking zone.