Defensive shifts have been pointed to as a prime issue dampening the impact of big league bats, and yet the batting average on balls put in play last season actually went up two points. The conundrum with offense in today's game is that the ball is not put in play enough. The strikeout rate has reached a new all-time high each of the last eight seasons, for K-ing … err, crying out loud.
We can certainly point to issues in approach or bullpen usage patterns as contributing factors in the offensive decline. Those are worthwhile topics to tackle. But let's not lose sight of one culprit in the rise of the K:
The strike zone itself.
On Friday, Yahoo! Sports' Jeff Passan reported that MLB was considering altering the textbook definition of the strike zone for the first time since 1996, when it was extended "from the top of the knees to the bottom." Why is this generating so much discussion now?
Part of it has to do with technology.
Defined by rule but enforced by man, the strike zone has always been open to interpretation. Ideally, it's a 17-inch-wide rectangle that extends basically from the armpit to the hollow beneath the knee, but ideals and actualities are rarely more than distant relatives. Because human beings are involved, the strike zone generally comes across more as suggestion than stipulation, and it has always been incumbent upon the hitter to recognize what, on a given day, constitutes a ball and a strike and to act accordingly.
In recent years, however, the suggestion of what, exactly, is a strike has expanded considerably.
We know this thanks to PITCHF/x, the tracking system that has been installed in every Major League stadium for nearly a decade now. I'll refer you to this terrific article written by Jon Roegele and published last October by the Hardball Times, but the gist of the situation is that the PITCHF/x-calculated square footage of the strike zone has increased nearly nine percent since 2008.
This is mostly attributable to a growing emphasis on the high and low portions of the zone. Ever since the 2001 introduction of QuesTec, umpires have been implored to enforce the high strike. But the increased proliferation of sinkerballers has only amplified the percentage of low stuff that must be considered, too. And the response, according to that Hardball Times data, is overwhelming: In just the last five years, the low portion of the zone has expanded basically by the diameter of a baseball -- to the point that it is, on average, pretty much as tall as it is wide. As a result, batters are taking (and missing) more swings low in the zone.
The zone's expansion might be more understandable when you consider the way umpires are evaluated in today's game. QuesTec went out the window in 2009, but the basic technology still exists in the form of Zone Evaluation (or Z.E.), which uses pitch-tracking data to rate umpire performance in enforcing the zone.
What's notable about that evaluative process is the two-inch buffer built into the system surrounding the strike zone. Because of that buffer, a pitch two inches below the kneecap that is called a strike might be technically incorrect, but the ump is still given credit for a correct call in the system.
The buffer zone is an inherent admission that no human being is eagle-eyed enough to correctly assess the strike zone within a matter of millimeters. Makes sense.
But the concept of being a "pitcher's umpire" seems prevalent enough that this buffer is bound to lead to extra strikes far more frequently than it does extra balls. Basically, if you know the "strike zone," in terms of your evaluation, is two inches wider, taller and lower than drawn up in the rule book, wouldn't you err on the side of strikes on borderline pitches?
Instant replay might have limited the frequency of umpire-manager arguments, but there were actually more ejections in 2014, the first year of replay, than there were in '13. That's because the strike zone remains a consistent center of contention, amplified all the more by a proliferation of new faces behind the mask in '14 (there were seven "rookies" appointed to full-time positions before Opening Day alone).
So what we have right now is an interesting juxtaposition of umpires coming of age in the Z.E. era and hitters coming of age at a time when on-base percentage is emphasized.
Strikeouts are the biggest byproduct of this pairing.
The last seven seasons account for the top seven averages in pitches per plate appearance since 1990, when STATS LLC first began tracking that stat. Not coincidentally, the 12 lowest first-pitch swing percentages since 1990 have all been logged in the last 12 seasons.
Hitters are waiting for their pitch like never before. Yet umpires are calling more and more of those pitches strikes.
This is a good combination for K rates, but not much else.
At a time when the baseball industry is abuzz with ideas about how to increase offense -- from the elimination of shifts (definitely not gonna happen) to meddling with reliever usage rules (probably not gonna happen) -- it could be that the quickest, easiest and, yes, most subtle way to inject more action into the game would be to tighten up the zone, perhaps even eliminating that Z.E. buffer. And, according to Passan's report, that's just what the league may do.
Granted, this idea runs the risk of prolonging -- if not expanding -- concerns about time of game, because an increased proliferation of walks wouldn't exactly tighten things up. But taking away a pitcher's below-zone cushion would force them in the zone more frequently and perhaps even inspire an increased -- and welcomed -- sense of aggression on the part of the average big league batter.
It's funny how cyclical this stuff can be. In 1987, Sports Illustrated ran a Peter Gammons-penned piece called "What Ever Happened to the Strike Zone?" -- a lamentation about the death of the high strike.
"In their desire to get more hitting in the game," Gammons wrote, "the owners have made rule changes that for the most part have been pro-hitter, anti-pitcher. Thus, the smaller strike zone has been winked at."
Maybe it ought to be winked at again.
Anthony Castrovince is a Sports on Earth contributor and MLB.com columnist. Follow him on Twitter @Castrovince.