The Rise (and Fall) of the MLB Strike Zone

During the 1990’s, Major League Baseball had experienced a near crippling player’s strike that cut short what would have been one of the most memorable seasons in baseball history in 1994: Matt Williams had hit 43 HR in just 112 Games, and Tony Gwynn was hitting .394 chasing the infamous .400 BA mark. This also ignores the memorable surge of the Montreal Expos and their potential chase to being World Series champions, which unfortunately was axed completely leaving them to eventually gut their system by 1998.

As the 1990’s came back, the memorable home run chase by Mark McGwire and Sammy Sosa lit up television screens worldwide as both chased and eventually topped Roger Maris’ mark of 61 set in 1961. While the home runs were becoming the big factor in drawing eyes to baseball and boosting its ratings, there was quietly a war going on behind the plate related to umpires and their enforcement, or lack thereof, of the strike zone. Umpires began to redefine the strike zone laterally taking out the high strike at the letters of the hitter’s jersey while also starting to rely more on the ‘framing’ of catchers (when a catcher would catch the ball outside the strike zone, then draw their mitt inside in hopes for a called strike). As a result of this, pitchers were forced to a much smaller window that often left pitches over the heart of the plate or resulted in a rise in walks as batters began to crowd the plate more to take the outside corner and send the ball to the opposite field because they were no longer being challenged inside.

The 1997 NLCS Game 5 was a particularly egregious example of a vastly wide “strike zone” (loosely used) by home plate umpire Eric Gregg. Livan Hernandez would strike out 15 batters in this game with the Atlanta Braves growing increasingly frustrated at the zone as the game wore on.

This partly came to a head in 1999 when the MLB umpires decided to stage a strike of their own against Sandy Alderson and Bud Selig. Alderson, the former GM of the Oakland Athletics in the 1980s and current GM of the New York Mets, had been hired by Selig to study the strike zone and try to challenge the umpires to call the strike zone better. The umpires refused and walked out with 57 of the 66 members handing in their resignations in a show of defiance. Unfortunately for them, Alderson gladly accepted their resignations and hired a slew of names from the minor leagues to take their spots. By 2004, most of the resigned had returned to MLB or been given retirement packages.

Pitchers relying on control suddenly started seeing their ERAs rise as the strike zone expanded. Greg Maddux had come off seasons of 2.20 and 2.22 ERAs in 1997 and 1998. Suddenly, his ERA spiked to 3.57 in 1999, 3.00 in 2000, and 3.05 in 2001. Those were numbers he had not experienced since the early 1990s and they were despite having a win-loss record of 55-29. From 2003-2008 as Maddux pitched into the twilight of his career, his control remained solid but he started giving up 200 or more hits a year and had a 4.13 ERA in 205 starts.

David Wells was another control pitcher and finished 71-32 from 1997-2000 despite a 4.17 ERA during that span and leading MLB in hits allowed in 1999 (246) and 2000 (266). In 1999 he finished a very good 17-10 but had career highs in home runs allowed with 32 and walks given up with 62. His 2.4 walks per 9 innings average was the highest for him since the 1991 and 1992 seasons, much like Greg Maddux.

By 1995, the strike zone was already having an influence across the entire MLB spectrum as the league tried to settle back from their 1994 player’s strike playing just 144 games. The 1995 numbers below have been pro-rated over 162 games for a better comparison to the following seasons aftewards.

1995 MLB: 4.45 ERA … 16,019 Walks … 4,591 Home Runs … 7,828 Doubles … .417 Slugging %***
1996 MLB: 4.60 ERA … 16,093 Walks … 4,962 Home Runs … 7,987 Doubles … .427 Slugging %
1997 MLB: 4.38 ERA … 15,666 Walks … 4,640 Home Runs … 8,004 Doubles … .419 Slugging %
1998 MLB: 4.42 ERA … 16,447 Walks … 5,064 Home Runs … 8,741 Doubles … .420 Slugging %
1999 MLB: 4.70 ERA … 17,891 Walks … 5,528 Home Runs … 8,740 Doubles … .434 Slugging %
2000 MLB: 4.76 ERA … 18,237 Walks … 5,693 Home Runs … 8,901 Doubles … .437 Slugging %
2001 MLB: 4.41 ERA … 15,806 Walks … 5,458 Home Runs … 8,813 Doubles … .427 Slugging %
2002 MLB: 4.27 ERA … 16,246 Walks … 5,059 Home Runs … 8,700 Doubles … .417 Slugging %
2003 MLB: 4.39 ERA … 15,889 Walks … 5,207 Home Runs … 8,827 Doubles … .422 Slugging %
2004 MLB: 4.46 ERA … 16,222 Walks … 5,451 Home Runs … 8,919 Doubles … .428 Slugging %

The effects of the umpiring change were immediately noticeable as soon as the 2001 MLB Season. Fewer walks were being called and pitchers were no longer being batted around nearly as mercilessly. Most of the numbers had trended back to the era of the mid 1990’s although the can of worms had already been opened in terms of players trying to hit for the home run regardless of the position they played. It was hard not to want to be that style of hitter after seeing moon shots from players such as Mark McGwire and knowing an extra 4-6 home runs could be the difference between a career in the big leagues and spending life at the Triple A level.

Even middling players never known for their power started showcasing an ability to hit for some power such as Luis Alicea, a lightweight second baseman. He usually was good for 4-5 HRs in a given season but was known for his glove and decent batting average yet in a combined 1998-1999 he hit 25 doubles and 9 home runs while walking 65 times in just 423 at bats. As players such as Tony Phillips started swinging for the fences and forcing pitchers to have to throw around the plate, they started seeing their power and discipline boom. By 1995 despite being 36 years old, Phillips would hit 27 home runs, draw 113 walks, and strike out 135 times. The next year at 37 years old he would hit 12 home runs, lead MLB with 125 walks, and strike out 132 times.

While the shrunken strike zone certainly helped out hitters and hurt some pitchers, it also helped the typical power pitchers rack up more strikeouts as a result of hitters taking what they thought were balls for called strike threes or being forced to swing at outside pitches after the umpire had established a wider strike zone than normal. Since the letter high strike was nearly outlawed, pitchers had to resort to trying to pitch just off the plate and hope the umpire had a slightly wider strike zone than what was recommended by the rule book. The Pedro Martinez example below, where he struck out 17 batters, is one where you can also see the influence of a catcher’s framing getting called strikeouts.

Martinez would see his strikeout numbers drastically jump from 222 in 216.2 IP as a young flamethrower in 1996 to a nearly improbable 313 in 213.1 IP in 1999 and 284 in 217 IP in 2000. Randy Johnson’s strikeout numbers were even more eye popping as he was in his late 30’s by the time he was leading MLB in strikeouts. In 1993, he had set his previous best with 308 strikeouts in just 255.1 IP. Yet he was vaulting himself way past those numbers just a handful of years later.

1997: 291 strikeouts in 213 IP
1998: 329 strikeouts in 244.1 IP
1999: 364 strikeouts in 271.2 IP (Johnson led MLB in IP)
2000: 347 strikeouts in 248.2 IP
2001: 372 strikeouts in 249.2 IP
2002: 334 strikeouts in 260 IP (Johnson was 38 years old yet would win his 4th straight NL Cy Young)

As we head into the start of Opening Day in 2015, MLB has continued to see a steady shift back towards pitchers with numbers far closely resembling the 1980s as opposed to the slugfest of the late 1990’s and early 2000’s. Last year, pitchers had a combined league wide 3.74 ERA while allowing just 4,186 home runs and striking out almost 3 batters for every batter walked. MLB’s league ERA has steadily been falling since 2012 with no signs that it will vault back to the inconsistent strike zone of the late 90’s/early 00’s anytime soon.