Baseball by the numbers: What a revised strike zone would mean

By John Grochowski

The strike zone has been defined, refined and redefined repeatedly since the birth of the National League in 1876.

The current zone has been in effect only since 1996. So when Major League Baseball’s competition committee recommended last week that the bottom of the zone be raised, it was following a well-trodden path.

In the expansion era, which started in 1961, we’ve seen four adjustments to the strike zone. Let’s take a by-the-numbers look, with the caution that the strike zone is always a piece of a larger puzzle, with multiple causes for offensive ebbs and flows.

1963: Expansions from eight teams to 10 in the American League in 1961 and the NL in 1962 had execs worrying there wouldn’t be enough pitching to go around. Fears were fueled when Roger Maris hit a record 61 home runs in 1961.

With a strike zone from the armpits to the top of the knees, teams averaged 4.53 runs in 1961 and 4.46 runs in 1962, minor blips after 4.31 in 1960 and 4.38 in 1959.

In 1963, the zone was extended to the top of the shoulders and the bottom of the knees. Offense plummeted to 3.95 runs per game. The average was 3.42 in 1968, the fewest runs per game since the all-time low of 3.38 in 1908.

1969: The strike zone was re-established as the armpits to the top of the knees. The mound also was lowered from 15 to 10 inches.

Scoring recovered to 4.07 runs per game in 1969 and rose to 4.34 in 1970, but it dipped back to 3.89 and 3.69 the next two seasons. That led the AL to adopt the designated hitter in 1973.

1988: In a fine-tuning, the top of the strike zone was changed from the armpits to the midpoint between the top of the shoulders and the top of the uniform pants.

Scoring patterns don’t find any major effect, with 1987 an outlier at 4.72 runs per game. The previous four seasons were at 4.31, 4.26, 4.33 and 4.41 and the next four slightly lower at 4.14, 4.13, 4.26 and 4.31.

1996: The highest-scoring era since the 1930s was just beginning, with 4.92 runs per game in 1994 and 4.85 in 1995. Expanding the bottom of the zone to the hollow beneath the kneecaps couldn’t stop the explosion. The 5.04-run average in 1996 was the first to top five since 5.19 in 1936.

With 1999 (5.08) and 2000 (5.14) also above five, scoring stayed high through 2007 (4.80).

After that, scoring declined seven seasons in a row, bottoming out at 4.07 in 2014. There was a modest increase to 4.25 in 2015, and this season is on about the same pace (4.29). Strikeouts are at 7.99 per team per game. That would top the record of 7.71 set last season, a record that has risen yearly since the 6.77 of 2008.

If a return to the 1988 zone is adopted, the hope is it will bring offensive recovery with more balls in play and fewer strikeouts.

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