MLB Strike Zone Rule Changes

The strike zone in Major League Baseball is always an exciting topic of discussion. It’s probably the one rule most subject to human error in all of professional sports and it’s the part of the game that we all like to share our opinions about; “that was outside”, or “that looked good to me” ring through baseball stadiums across America.

May fans may not know that the strike zone hasn’t always been the same. MLB has changed the Strike Zone rules many times over. Here’s a brief history of some of those changes.

In 1876, the Strike Zone rule read like this.
“The batsman, on taking his position, must call for a ‘high,’ ‘low,’ or ‘fair’ pitch, and the umpire shall notify the pitcher to deliver the ball as required; such a call cannot be changed after the first pitch is delivered.”

But, in 1887 this rule was revoked and it began to look more like the rule we’re familiar with today.
“A (strike) is defined as a pitch that ‘passes over home plate not lower than the batsman’s knee, nor higher than his shoulders.'”

Between 1987 and 1949 there were several rule modifications that further defined what a strike was and what a ball was but the next significant rule change happened in 1950 when the Strike Zone changed from the top of the shoulders and bottom of the knees to the armpits and top of the knees.

“The Strike Zone is that space over home plate which is between the batter’s armpits and the top of his knees when he assumes his natural stance.”

In 1963 the rule changed again to read,
“The Strike Zone is that space over home plate which is between the top of the batter’s shoulders and his knees when he assumes his natural stance. The umpire shall determine the Strike Zone according to the batter’s usual stance when he swings at a pitch.”

However, this didn’t last long and it changed right back in 1969.
“The Strike Zone is that space over home plate which is between the batter’s armpits and the top of his knees when he assumes a natural stance. The umpire shall determine the Strike Zone according to the batter’s usual stance when he swings at a pitch.”

In 1988 we saw, perhaps, the most significant Strike Zone rule change since 1950. The top of the Strike Zone was lowered.
“The Strike Zone is that area over home plate the upper limit of which is a horizontal line at the midpoint between the top of the shoulders and the top of the uniform pants, and the lower level is a line at the top of the knees. The Strike Zone shall be determined from the batter’s stance as the batter is prepared to swing at a pitched ball.”

The most recent rule change happened in 1996. This was also a significant Strike Zone rule change because it lowered the bottom of the Strike Zone to the bottom of the knees again.