The Strike Zone That’s Eating Baseball

It’s not exactly breaking news that the major-league strike zone has been expanding for quite some time now. For this essay, I tried to read up on the phenomenon so I could write about how much it’s been expanding, its impact on the game, why it’s happening, and how long it might continue.

But first, we need some context. Specifically, we need the context of 1968, the worst year for offense in the modern era of major-league baseball.

In his dated but still excellent book The Summer Game, Roger Angell wrote, “The 1968 season has been named the Year of the Pitcher, which is only a kinder way of saying the Year of the Infield Pop-Up.”

In 1968, only six major-league hitters finished with a batting average above .300, five of them in the National League. Carl Yastrzemski won the American League title with a BA of .3005.

In 1968, Bob Gibson’s earned run average was 1.12, lowest in NL history. Denny McLain became the first 30-game winner (31-7) since Dizzy Dean in 1934. Luis Tiant allowed a batting average of .168. Both league MVPs were pitchers. The White Sox were shut out 23 times. There has never been a season, in the modern era, when pitching was so dominant.

Here’s a look at selected hitting stats from 1968, matched with last season for comparison.

Stat 1968 2014
Runs per game 6.8 8.1
Batting Average .237 .251
On-Base Pct. .299 .314
Slugging Pct. .340 .386
Earned Run Average 2.98 3.74
Complete games 897 118

After the 1968 season, the Lords of Baseball feared they were alienating the average fan with “boring” low-scoring games so they reduced the strike zone and lowered the pitcher’s mound – from 15 inches high to 10 inches, where it remains today.

The results were immediate and salubrious. The following season, 1969, saw almost every batting rate stat increase, some significantly. Runs per game went up about 20%. Home runs increased by more than 50%.

But here’s another stat line that is not only interesting and puzzling, it also gets to the point of this piece.

Stat 1968 2014
Strikeouts per game 5.9 7.7

In 1968, the Year of the Pitcher, the major weapon in the pitcher’s arsenal was less dominant than it was last season. The strikeout rate in 2014 was really high. In fact, it was higher than it has ever been. Here’s a table with total strikeouts for the past ten seasons.

Season Total Strikeouts
2014          37,441
2013          36,710
2012          36,426
2011          34,488
2010          34,306
2009          33,591
2008          32,884
2007          32,189
2006          31,655
2005          30,644

You can see that total strikeouts have increased every year since 2005. What’s not obvious is that each of those increases represents a new MLB record. How come? Did something change? Yes, of course. The strike zone changed, dramatically and deliberately.

There has been some excellent, in-depth analysis of the rate and magnitude of that change, which I, as a former journalist, am not qualified to replicate. (The founder of Intel, the late, great Robert Noyce, once told me, “They had to invent majors like English and journalism for people who can’t do math.” Amen.)

Here’s a piece from Ben Lindbergh, at Grantland, whose work includes some great interactive graphics that pinpoint how much, and where, the strike zone has grown.

Here is an academic paper from Brian Mills, University of Florida sports management professor. Mills also posted this graph on Twitter, which shows two things: the called-strike rate is on the rise and umpires are more consistent with their called strikes – there are fewer outliers.

And here is the latest from John Rogele at The Hardball Times/Fangraphs. This table lists the actual size of the called-strike zone by year, and how it has grown downward.

Year Strike Zone Size(sq. in) Strike Zone Size Below 21”(sq. in)
2009 435 0
2010 436 6
2011 448 11
2012 456 19
2013 459 30
2014 475 47
2015* 477 50

* Through July 31 

And this graphic shows the actual size of the called-strike zone today, for lefties and righties, from the umpire’s perspective. (Graph courtesy of Fangraphs)

We don’t have the tracking data to chart strike zone size before 2009 but we do have the called-strike rate – how often a pitch that a batter takes is called a strike – since 1988. And here it is:


The rate of called strikes has been gradually rising since 1988, and – according to Lindbergh – would account for about one-third of the recent scoring decline.

Notably, about 90 percent of this called-strike rate increase has occurred since 2000 – when Barry Bonds hit 46 home runs, 45 percent more than he hit in 1999. The called-strike rate has continued to zoom upwards. This is not, in my opinion, a coincidence.

I’m not going to sermonize about steroids and other PEDs here. And I need to reinforce that Lindbergh, Roegele and Mills do not mention steroids in their cited works. No respected analyst has been able to demonstrate a statistical connection between PED use and increased home runs.

But consider these facts:

-In 1998, Sammy Sosa and Mark McGwire both broke Babe Ruth’s home run record. That launched a home-run hitting rampage that hadn’t been seen since the days of the 1929 Yankees. It also started a national whisper campaign about the use of steroids.

-After the 1999 season, the commissioner’s office merged the AL and NL ump crews, which provided tighter control over umpire performance.

-After the 2000 season, the QuesTec system was installed at ballparks, and MLB ordered the umps to start calling more strikes – ostensibly to shorten game times.

-In 2001, Bonds cracked 73 home runs, a spike of 63% over his previous career high. The steroid whispers grew in scope and volume and commissioner Bud Selig finally got the Players Association to agree to testing for steroids. (They’d already been outlawed, in the early 1990s, but this was the first enforcement attempt.)

Is it reasonable to conclude that Selig was also eager to use his new umpire authority to expand the strike zone, reduce offense and make his new PED testing program appear successful? Selig clearly wanted to erase the steroid stain from baseball. If that meant deliberately sacrificing offense with a bigger strike zone, well, so be it.

And here we are. Scoring is at its lowest since 1981, which was predictable. A somewhat less obvious consequence was the impact on Moneyball’s favorite statistic, On Base Percentage. Last season, league OBP was the lowest it’s been since 1964. Obviously, this is a direct result of the highest strikeout rate in history combined with the lowest walk rate in 125 years.

If you want an example that’s pretty close to home, take a look at Shin-Soo Choo.

When the Rangers signed him, he’d had seven straight seasons wherein his OBP averaged better than .380. In 2013, with Cincinnati, it was above .400. Today, it’s .319 – about league average.

So the primary component of his value as a hitter, which played a big role in the huge contract the Rangers gave him, has disappeared into the ravenous maw of the expanding strike zone.

Yes, he’s been injured. Yes, he’s a couple of years older. But I think the big factor is, his confidence at the plate was been shaken by the “lefty strike,” the down-and-away pitch that umps called a strike.

Choo is just one example of the patient, thoughtful hitter who spent years mastering knowledge of the strike zone only to find that it keeps changing, to his detriment. Now, the skill that was the cornerstone of his career has become all but useless.

It’s a simple equation: when the strike zone expands, pitchers have more area to exploit and hitters have more area to defend. When it expands down and away, pitchers gain an immediate and lasting advantage smack in the region where most batters achieve their lowest, weakest contact rates.

Baseball is a game that, more than most sports, depends for its appeal on a delicate balance among hitting, pitching and fielding. Currently, the data shows that we are watching an imbalance of near-historic proportions, second only to the Year of the Infield Pop-Up.

MLB Commissioner Rob Manfred said earlier this year that the league will spend the 2015 season looking at ways to “inject” (poor choice of words) more offense into the game. He mentioned outlawing the shift, but I think that was a smokescreen. I assume the league is going to rein in the strike zone.

It might have already happened. Roegele, Mills and others think instances of the “lefty strike” are down this year. Shin-Soo Choo fervently hopes so.

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FOOTNOTE: Roger Angell, 94, senior editor for the New Yorker magazine, last year received the Baseball Hall of Fame’s J.G. Taylor Spink Award for writers. He’s the only Spink honoree who is not a member of the Baseball Writers Association of America. Think about that.

I’ll keep my BBWAA opinions to myself, but I know this: I was once a BBWAA member and my contributions to the craft do not compare in any way to Angell’s. Consider this:

“”Since baseball time is measured only in outs, all you have to do is succeed utterly; keep hitting, keep the rally alive, and you have defeated time. You remain forever young.”


Angell’s The Summer Game (mentioned above) is a leisurely discussion of baseball’s decade of the 1960s. It has a pronounced New York perspective but it’s well worth a read by any baseball fan, regardless of age or geography. At one point, it includes a discussion of hitting versus pitching that is still relevant today. Since it didn’t advance our strike zone story, I couldn’t include it, but I have pasted some of it below, in case you’re interested.

– – – –

“Hitting has nothing much to do with increased size or strength but is almost wholly a matter of reflexes. A number of thoughtful students of athletics, including Ted Williams, consider hitting a baseball to be the most difficult reflex – the hardest single act – in all sports.

“Almost any strong and passably coordinated young man can learn to pitch, but batting is not generally teachable; even after a lifetime in the game, most pitchers still swing like their old aunties. The solid-gold reflex of the natural hitter is capable of some polishing, but  only through many years of practice.”

Joe Stroop
I was a sports reporter in DFW throughout the 70s and 80s. I'm a former member of BBWAA and shared the Arlington Stadium press box with all the big boys. I'm here to remind you of the past. I own a Nokona.

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