Foul Ball Rates: 3 Ball Rise per MLB Game in Nearly 30 Years

Over the years there have been a number of assertions made about foul ball rates, particularly the number of foul balls hit per Major League Baseball game on average. Speculation and random ball counts have


been performed, but nothing that has been in-depth all. The most recent assertion comes in the foul ball injury lawsuit Gail Payne and others filed against Major League Baseball in July 2015 and amended in October 2015.

Several lawsuits concerning foul ball injuries over the course of the last decade have cited the “fact” that there are significantly more foul balls being hit each season and that they are going much faster than 100 years ago. However, the “significant increase” is inaccurate. The data show there’s been a statistically insignificant boost in foul rates in the last 30 years.

I’ve tallied the years 2011-2014 and compared them with the years of foul balls already totaled. What we are hearing from lawyers filing suits against MLB teams is the assumption there are significantly more foul balls now than 100 years ago, 20 years ago and even 10 years ago.


Foul Ball Rates Appear to Increase

Are there more foul balls?


But the increase is not “significant” in any manner.





What we see in these most recent four years is evidence of a 2.5 ball increase over the period of 17 years and not quite three in nearly 30 years.

That is less than one extra foul ball per game every three years. Such a change is marginal and statistically insignificant.


Reasons for the Increase are Many

Some of the factors that affect rates include:

  • Changes in bats
  • Changes in balls
  • Changes in types of pitches
  • Changes in batting match-ups
  • Changes in number of elite players
  • Weather (Global Climate Change?)
  • Improved pitching
  • Improved batting
  • Doctoring of balls and/or storage


All of these influences will force players—both pitchers and batters—to adjust the way they play and how they react to one another.

To put the increase into some perspective, the apparent 2.5 ball rise since the start of interleague place accounts for about half a percent of the total average of foul balls per game. When we consider there are on average 81 home games, the 2.5 increase does appear to be significant, accounting for about 202 additional foul balls per season during home games, or roughly 4.5 games worth of foul balls.

However, in the grand scheme, the number is insignificant.

Thus, what explains the marginal, statistically insignificant increase is anything. While this seems dismissive, it isn’t. Assuming the missing decade shows a similar pattern, the culprits could be many: A hotter-than-usual summer or day would certainly affect the speed and elasticity of balls and thus cause batters to adjust. Due to the decreased drag on the ball they will play to the way a pitch responds and moves in that 60’ 6” from the mound to the plate. A particularly dry or wet summer or day would influence the way the ball behaves.

With as many elite or nearly-elite pitchers, there will be an uptick in batters chasing “bad” pitches, often fouling them off because of the weather alone. Given there’s evidence that the most recent summers have been some of the hottest on record, and that some areas, like the Midwest (Illinois, Minnesota, Michigan, Ohio, Indiana, Wisconsin, Iowa) have tended to be a bit more humid while California and other western states have dealt with droughts. These weather changes in and of themselves could account for a slight uptick. Foul ball rates aren’t simply predicated on the idea of faster pitches and bigger, stronger batters.

Another reason could be that more pitchers are studying the batters they will face and are more adept at keeping them off balance.

It could be that the DH in the AL has made a significant contribution as well. While the pre-Interleague numbers for the AL were lower than those of the NL up to the 1996 season, The AL averages now appear to marginally outpace those early NL rates. Designated hitters are more adept at picking up the seams of the ball to judge the type of pitch in the 150 milliseconds (Physics; reaction time website) they have to make a decision; because of this skill, they won’t foul off as many pitches as the pitcher will in the NL, who has a higher propensity for hacking away in an effort to jump the pitch count of their opponent.

This may be the reason for the increase since 1997 too. When teams played only other league teams, they better understood the pitchers; hence the barely perceptible increase in foul ball rates between 1988 and 1996. All batters, but particularly the DH/Hitting Pitcher changes for both leagues, had to adjust to different pitchers who they might see one to two times during a season rather than upwards of a dozen times.

One thing is for certain in all this: There has been an increase. The increase, however, has taken place over the course of 30 years, give or take, and is insignificant statistically. A 2.5 foul ball increase over the course of 81 games, is hardly cause for alarm. A sub-three (2.9) ball increase in 30 years is also insignificant.