Jordan Zimmermann woke up Tuesday morning, read the report from the Associated Press that MLB appears to be considering a raising of the strike zone, yawned, took another sip of coffee, and quietly went back to working on the day’s crossword puzzle from The New York Times.
According to the AP’s interview with commissioner Rob Manfred, MLB is “studying whether to raise the bottom of the strike zone from the hollow beneath the kneecap back to the top of the kneecap.” We know that offense is as low as it’s been in 25 years with strikeouts at an all-time high, and while that’s partially due to ever-increasing velocity and changes in approach, it’s also got plenty to do with a strike zone that’s larger than any we’ve got on record, with the brunt of the expansion found in the lowest sliver of the zone. MLB can’t change how hard pitchers throw or where they put it, so the logical step, if they’d like to inject some offense back into the game (though it did come back up for the first time in six years last season), would be to rein in the strike zone a bit. If a change is made, it likely wouldn’t come until the 2017 season at the earliest, as it’s a matter to be discussed in collective bargaining negotiations, the results of which wouldn’t impact the league until the current CBA expires on December 1, 2016.
Raising the floor of the strike zone wouldn’t much affect Zimmermann, who pitched above the waist more than any pitcher in baseball last year. But certain guys make their living down in the zone, around the very sliver that’s being discussed as turning from a called strike to a called ball.
Pictured on the left of each image is the strike zone, as it was called in 2009. On the right, the strike zone as it was called in 2014. While the outside zone against left-handed batters has shrunk since 2009, the bottom of the zone against both lefties and righties has grown substantially, and that’s what’s currently being viewed as the problem area.
Were a change to be made, it’s unclear precisely what it might be; no specifics were mentioned in the AP report. But I’d think it’s reasonable to assume they’d be aiming to get back to something like the 2009 standard. At least, that’s the assumption under which we’ll be operating for the remainder of this post.
So, what we’re looking at here is a section of the zone, between 1.5 feet and about 1.75 feet above the dirt, in which pitchers didn’t used to get called strikes, but where they are getting called strikes, now. For some pitchers, this is an area which they’ve been targeting their whole lives. Others have tailored their approach to take advantage of the expanded zone. Any change made by MLB wouldn’t be targeting specific players, but it would affect certain players more than others. Who might those guys be, and what might be the magnitude of a shift?
Using BaseballSavant‘s advanced PITCHf/x search, we can identify the pitchers who most targeted the sliver of the zone between 1.5 and 1.75 feet off the ground. What follows are the 20 pitchers who attacked this part of the zone at a rate that was more than one standard deviation above league average:
|Player||Total Pitches||> 1.5 < 1.75||> 1.5 < 1.75 %|
|Rubby de la Rosa||3012||303||10.1%|
It’s an even split of lefties and righties, and the table is populated by plenty of sinkerballers. By a raw count, it’s Gibson, Keuchel, and Miley who threw the highest number of pitches in the specified zone, but Wood who actually lived there the most.
But, while this gets us close to what we want to know, it doesn’t quite get us all the way there. Not every pitch in this zone is made the same. Some guys are trying to work outside the zone when they pitch low, others inside. Some guys work there in different counts. Some pitch low to contact, others pitch low to whiffs. The guys who would hypothetically be most affected by a change are the ones who rely on this area of the zone for called strikes.
Another table, this time showing the leaders of called strikes on pitches 1.75 feet off the ground or lower:
|Player||Total Pitches||CS < 1.75||CS < 1.75 %||kL < 1.75|
The samples are smaller, and surely there’s noise in the data, but you see plenty of repeats and we see who our big losers could be. The names aren’t too surprising: Hendricks, Niese, Keuchel, Miley, Lohse, Leake, Liriano. These guys pounded the lower part of the strike zone and depended on it for called strikes more than anyone. At the most extreme level, they earned up to 100 called strikes, or more, in a zone that was called a ball as recently as 2009.
This is a very complex subject. It wouldn’t be nearly as simple as turning all of the called strikes into balls and calling it a day. Framing changes the math, and so do the human elements of the umpires, and batters who have changed their approach in the last five years and would have to do so again, if a change were to be made. Pitchers would have to make subtle tweaks to their approaches too, especially the ones listed in the tables above. All of this considered, and certainly more, we’ve no idea how many of these called strikes pitchers would actually lose.
But let’s use Keuchel as an example, and look at a possible range of over-simplified outcomes. Last year, Keuchel got a league-high 130 called strikes in the target area. The run value of the difference between a ball and a called strike is something like 0.128 runs per pitch, and that might be on the conservative side. If we turned all 130 of Keuchel’s called strikes into balls, that’s more than 16 runs, enough to hypothetically boost last year’s ERA from 2.48 to 3.10. Of course, the actual effect wouldn’t be anywhere near that large. He’d simply throw less of these pitches, and not every pitch in the target area would be called a ball. But even 50% is eight runs, hypothetically moving the ERA from 2.48 to 2.79. At 25%, it goes from 2.48 to 2.64.
A league-average starter had a 4.10 ERA last year, and got something like 66 called strikes in the target area. Performing a similar exercise, which again is admittedly a very rough calculation that accounts for exactly zero outside factors, we find a range of outcomes something like this:
|Strikes to Balls||Hypothetical ERA|
When Roegele very thoroughly imagined a redefined strike zone last summer, he concluded, among many other fascinating findings, that a return to the 2009 strike zone would increase a team’s runs per game from 4.07 to 4.27, which matches up well with the median outcome of my simple-minded fool’s table above.
Raising the strike zone, certainly, would inject some offense back into baseball; that’s MLB’s endgame in this endeavor. While it might not come for a couple more years, it will be fascinating to see how our most extreme low-ball pitchers adjust, if and when the change is made, or perhaps even preliminarily, now that the seed’s been planted. If there’s anything we can conclude from Manfred’s inaugural season as commissioner, it’s that he’s nothing if not proactive.
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