The Athletic obtained an internal memo Major League Baseball sent to general managers, assistant general managers, and equipment managers last Friday. The Memo outlined the minor changes to the baseball construction that might combine to reduce offense slightly in the 2021 season. "In an effort to center the ball with the specification range for COR and CCOR, Rawlings produced a number of baseballs from late 2019 through early 2020 that loosened the tension of the first wool winding," the memo from the office of the commissioner reads. According to the memo, this change will have two effects — "reducing the weight of the ball by less than one-tenth of an ounce, and also a slight decrease in the bounciness of the ball as measured by the COR and CCOR."
For those who aren't familiar with it, "COR" is the coefficient of restitution or the incoming speed's relationship to the outgoing rate. So in simpler terms, the COR number determines how "bouncy" the ball is and how the humidity affects baseballs' speed and direction.
In 2019, Major League Baseball conducted an independent study done by Dr. Jim Albert of Bowling Green University, Peko Hosoi of MIT, Dr. Alan Nathan of the University of Illinois, and Dr. Lloyd Smith of Washington State University.
According to the 27-page report released, the increased amount of home runs in 2019 "could be attributed to the inconsistent" baseball seam heights and players embracing launch angle. "No evidence was found that changes in baseball performance were due to anything intentional on the part of Rawlings (the company that makes the league's official baseballs) or MLB and were likely due to manufacturing variability," the committee concluded in their report.
In an excerpt from the report: "Analysis of StatCast data shows that the increase in home run rate between 2018 and 2019 was due in part to a change in launch conditions and in part to a change in the baseball drag. The increase due to changes in launch conditions was determined to be due to a change in player behavior rather than to changes in the Baseball. ... The laboratory experiments, using newly developed techniques, show a correlation between drag and seam height, with the average seam height in 2019 smaller than that in 2018 by less than 0.001 inches."
The Athletic report cited a footnote from the memo that "says an independent lab found that fly balls that went over 375 feet lost one to two feet of batted ball distance with the new ball. That also sounds like no big deal, but every 3.3 feet of distance increases the likelihood of a home run by ten percent. An analyst familiar with the physics and math of this situation said the relationship was linear enough to estimate that this change will reduce home run rates by around five percent."
No matter what the outcome of the construction of the actual baseball will be, the impact it has on the game will likely be debated for years to come.
Edited by: Jonathan Mailloux
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