The Pitchers Hurt Most by a Higher Strike Zone

Major League Baseball has been floating a bunch of different ideas lately to help improve the game: automatic intentional walks, starting a runner on second in extra innings, and one that would likely have the most impact, raising the lower bounds of the strike zone.

If you feel like you’ve heard that last one before, it’s because you almost definitely have. Jon Roegele has been chronicling the expansion of the strike zone for years. It’s not just him, though. Just last year, there were reports that MLB planned to raise the strike zone. In response, August Fagerstrom discussed who might be affected the most. August isn’t around these parts anymore, so consider this post your update on the pitchers who might be negatively affected by a slightly higher strike zone.

First, consider the visuals below. They’re from a 2014 piece by Roegele and were reproduced by Fagerstrom last year. They documents how the strike zone has expanded downward over the last decade.

It’s pretty obvious from these graphs that pitches in the lower part of the zone were being called strikes more often in 2014 than five years earlier. But these images are from a couple seasons ago. Is it possible, given the talk last season about raising the strike zone, that umpires took it upon themselves to do it? To compensate for the lower-zone creep happening of late?

It’s a reasonable theory, just not one that can be substantiated by evidence. Roegele recently updated his work to include last season. The results? The strike zone is still rather large, especially at the bottom of the zone.

There was still a pretty high frequency of low strikes last season. Forcing pitchers to work higher in the zone, even by a few inches, would increase the number of swings batters are compelled to take and increase, at the same time, the number of balls in play. That’s the theory anyway.

If pitchers, facing a new zone, were nevertheless to approach hitters exactly as they did in 2016, the result would probably just be more called balls. Last season, in the low part of the zone between 1.50 and 1.75 feet above the ground, batters swung at 48% of pitches. In the area directly above it, though — between 1.75 and 2.00 feet — batters swung at 53% of pitches, per Baseball Savant. Of course, if pitchers are trying to hit the new lowest part of the zone, batters are more likely to swing in the area between 2.00 and 2.25 feet (57%).

It’s not just swings. As the table below illustrates, hitters make more contact at pitches up in the zone.

Swing and Whiff Rates on Pitches in Lower Part of Strike Zone
Distance Above Ground (feet) Swing % Whiffs/Swing % Contact per 100 pitches
1.50-1.75 47.6% 27.8% 34
1.75-2.00 52.6% 19.6% 42
2.00-2.25 57.2% 14.8% 49

Both swing rate and contact rate increase the higher a pitch gets in the strike zone. That’s pretty intuitive, of course: the closer a pitch is to the middle of the strike zone, the easier it is to hit. Assuming pitchers don’t want to throw more balls (and they don’t), they’ll be forced to throw more pitches slightly higher in the zone, which would presumably lead to more swing and more balls in play. It’s possible that hitters would adjust begin to offer at fewer pitches in the lower part of the zone. Possible but unlikely. Hitters swing at these pitches not just because they’re strikes, but because they’re good pitches to hit.

Let’s return briefly to the table above. In addition to swing rate and contact rate, another metric that increases with pitch height is slugging percentage. That starts at .354 in the 1.50- to 1.75-inch rage, up to .428 in the range above that, up to .499 in the range above that. If you believe that the strike zone should be comprised of the most hittable pitches, it isn’t clear the lower part of the current strike zone fits that description.

Last year, August hypothesized that the pitchers who would be affected the most are those who work most often in that lower part of the zone. Among the starters pitching low in the zone were Carlos Carrasco, Kyle Hendricks, Mike Leake, Jon Lester, and Alex Wood. Repeating that exercise with 2016 number produces the following results for starting pitchers.

Pitchers Utilizing the Lowest Part of the Strike Zone
Player Results Total Pitches % of Pitches
Kendall Graveman 324 2831 11.4
Kyle Gibson 281 2468 11.4
Martin Perez 350 3078 11.4
Zach Davies 288 2588 11.1
Jon Niese 223 2011 11.1
Yu Darvish 175 1579 11.1
James Shields 331 3133 10.6
Masahiro Tanaka 307 2935 10.5
Kenta Maeda 306 2930 10.4
Zack Greinke 259 2503 10.4
Jorge de la Rosa 242 2343 10.3
Luis Perdomo 245 2372 10.3
Mike Leake 274 2659 10.3
Jon Lester 321 3161 10.2
Ivan Nova 234 2310 10.1
Patrick Corbin 257 2539 10.1
Chase Anderson 266 2640 10.1
Marcus Stroman 312 3102 10.1
Wade Miley 273 2732 10.0
Dallas Keuchel 271 2720 10.0
Noah Syndergaard 289 2930 9.9
Wily Peralta 207 2132 9.7
SOURCE: Baseball Savant
“Lowest part of the zone” here denotes 1.50 feet to 1.75 feet above the ground.

Many of the same names carry over from last year. Now here’s the same table, except for relief pitchers.

Relievers Utilizing the Lowest Part of the Strike Zone
Player Results Total Pitches % of Pitches
Brad Ziegler 175 1035 16.9
Joe Smith 120 815 14.7
Steve Cishek 152 1074 14.2
Brandon Kintzler 104 828 12.6
Francisco Rodriguez 115 928 12.4
Andrew Miller 138 1118 12.3
Alex Claudio 96 789 12.2
Matt Albers 108 891 12.1
Jeremy Jeffress 104 867 12.0
Jeanmar Gomez 137 1154 11.9
SOURCE: Baseball Savant
“Lowest part of the zone” here denotes 1.50 feet to 1.75 feet above the ground.

These pitchers are still likely to utilize the same area to get swings, and it isn’t like moving his pitches a couple inches up is going to make Andrew Miller a bad pitcher, but as strikeouts have continued to go up and up over the last 10 years, getting the strike zone back to where it used to be is probably the easiest answer to curtailing that trend. (Expansion might be another answer, but it isn’t quite so simple.) Walk rates haven’t changed too much since the strike zone got bigger, so there isn’t a ton of reason to think that decreasing the strike zone will lead to a lot more walks.

Expanding on the charts above, here are the pitchers who would have lost the most called strikes last season.

Most Called Strikes in the Lowest Part of the Strike Zone
Player Results Total Pitches % of Pitches
Zach Davies 83 2588 3.2
Kendall Graveman 82 2831 2.9
Wade Miley 75 2732 2.8
Kyle Hendricks 79 2888 2.7
Jon Niese 54 2011 2.7
Ubaldo Jimenez 65 2492 2.6
Chase Anderson 67 2640 2.5
Marco Estrada 72 2843 2.5
Zack Greinke 63 2503 2.5
Archie Bradley 64 2575 2.5
SOURCE: Baseball Savant
“Lowest part of the zone” here denotes 1.50 feet to 1.75 feet above the ground.

At the other end of the spectrum, there are also pitchers who are not likely to be affected by a change in the lowest part of the strike zone. The group below, including both starters and relievers, rarely pitched in that area last year.

Pitchers with Fewest Pitches in Lowest Part of Strike Zone
Player Results Total Pitches % of Pitches
Kenley Jansen 41 1002 4.1
Steven Wright 104 2496 4.2
Bartolo Colon 135 2853 4.7
Edwin Diaz 40 831 4.8
Matt Barnes 60 1197 5.0
Junichi Tazawa 42 838 5.0
Alex Reyes 40 793 5.0
Zach McAllister 47 932 5.0
Kevin Quackenbush 52 1025 5.1
Rich Hill 93 1811 5.1
Daniel Norris 62 1190 5.2
Aroldis Chapman 51 972 5.3
Will Harris 56 1045 5.4
Julio Urias 76 1415 5.4
Justin Verlander 198 3668 5.4
Jake Odorizzi 182 3308 5.5
Trevor May 47 836 5.6
Trevor Rosenthal 50 856 5.8
Michael Fulmer 145 2473 5.9
Justin Miller 46 771 6.0
SOURCE: Baseball Savant
“Lowest part of the zone” here denotes 1.50 feet to 1.75 feet above the ground.

We know that the strike zone has gotten bigger, and that the area where the strike zone has grown tends to elicit (a) fewer swings, (b) more swinging strikes, and (c) a lower slugging percentage than other areas of the zone. We know that strikeouts keep increasing. The solution seems pretty obvious. It will affect the way pitchers pitch, and the way hitters hit, but for those who enjoy seeing the ball put in play, it is a sacrifice that pitchers, some more than others, will have to make for the sake of improving the game.

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Craig Edwards can be found on twitter @craigjedwards. His writing also appears regularly at where he is the Managing Editor.

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