There’s been an interesting yarn unfolding in MLB over the last half-decade. Call it The Incredible Expanding Strike Zone.

Whether it’s a fairy tale or a horror story depends on whom you ask.

Pitchers and fans who enjoy low-scoring games should applaud the growth of the strike zone, which has been exhaustively documented (more on that in a moment).

Hitters, fans of high-scoring affairs and baseball higher-ups concerned with the game’s popularity, on the other hand, should be sounding the alarm.

And they are, as Yahoo Sports‘ Jeff Passan reported Thursday:

Major League Baseball is considering altering the textbook definition of the strike zone for the first time in nearly two decades, fearful that the proliferation of the low strike has sapped too much offense from the game…

Concern around baseball about the strike zone filtered down to the MLB’s Playing Rules Committee, which must formally adopt a rules change before it’s implemented. The committee will pay close attention to the size of the strike zone in 2015 with an eye on change as early as 2016 after studies showed it has expanded significantly since 2009, coinciding with a precipitous dip in run scoring.

One of the studies Passan referenced comes from Jon Roegele of The Hardball Times

Using PITCHf/x data, Roegele found that in 2008 the average size of an MLB umpire’s strike zone was 436 square inches. By 2012 that number had ballooned to 456 square inches, and last season it jumped to 475 square inches.

More specifically, the zone is growing downward. Since 2009, Roegele notes, three inches have been added to the bottom of the zone, while the corners have tightened slightly. 

Studies like Roegele’s and this one from University of Florida professor Brian M. Mills are invaluable, injecting hard evidence into a fraught, emotionally charged debate. (At least as much as a debate about grown men throwing balls can be emotionally charged.)

At the same time, anyone who regularly watches baseball can bolster these findings with the eyeball test: How many called strikes have you watched in recent years that bit off more mid-shin than knee?

Correlation doesn’t equal causation, but last season’s super-sized strike zone coincided with a league-wide average of 4.07 runs per game, the fewest in more than 30 years, as Baseball-Reference shows.

So there’s a problem, or at least a growing concern, and MLB and new Commissioner Rob Manfred have taken notice. Now what?

First, it’s important to remember that the strike zone is a malleable, evolving concept.

In 1876, per, the batter (or, rather, “batsman”) was required to call for a “high,” “low” or “fair” pitch; basically, the hitter got to tell the pitcher where to throw the ball and the pitcher had to oblige. Talk about increasing offense.

Foul balls weren’t counted as strikes until 1901. The concept of calling balls wasn’t adopted until 1907. 

In 1969, the strike zone was defined as the “space over home plate which is between the batter’s armpits and the top of his knees…”

In 1988, the top of the zone was lowered to “the midpoint between the top of the shoulders and the top of the uniform pants.” Eight years later, the last time an official change was adopted, the bottom of the zone was redrawn to extend to the base of the knees.

Can the zone change again without unnecessary growing (or shrinking) pains?

Baseball has implemented a number of significant shifts in recent years: Reshuffled divisions, increased interleague play, the expanded postseason format, instant replayall have arrived with varying degrees of grumbling and hiccups, but nothing cataclysmic.

Players, managers, umpires and fans have adapted, and in some cases embraced, the changes.

The strike zone, though, is a unique animal, guaranteed to raise temperatures.

Umpires have cast a wary eye at balls-and-strikes technology (basically, machines designed to do their job) from the moment MLB began using QuesTec to monitor and standardize the strike zone in 2001.

Pitchers weren’t crazy about it either. Recall the infamous 2003 incident when Curt Schilling, then of the Arizona Diamondbacks, smashed a QuesTec camera during a loss to the San Diego Padres.

“I said something to one of the umpires about it,” Schilling said at the time, per the St. Petersburg Times, “and he said, ‘Do us a favor and break the other one.'”

Pitch-tracking tech has come a long way in the last decade. Nearly everyone accepts that it’s mostly accurate and, more importantly, here to stay.

We’re probably not headed for a day when umps wear earpieces and get balls and strikes fed to them by a machine (though that’s not a terrible idea). 

But a rule change that elevates the bottom of the zone will be easier to enforce with the use of available data, the numbers independent analysts like Roegele have already conclusively crunched.

Even with no changes, you’ve got to assume the zone will stop growing at some point. Umpires aren’t about to ring hitters up on pitches that buzz their shoelaces…right?

The question, though, is if this story will have a sequel, tentatively titled Honey, They Shrunk the Strike Zone.

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