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MLB making changes to the baseball for 2021 season

Expect the home run numbers to come down in 2021

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If you’re a fan of the home run, you may be seeing a little less of it in 2021.

According to Ken Rosenthal of The Athletic, the construction of the baseball will be changing slightly next season. On top of that, five more teams will be adding humidors for ball storage. This is part of Major League Baseball’s attempt to reduce increased number of home runs we’ve seen over the years.

In the report, The Athletic obtained an internal memo Major League Baseball sent Friday to general managers, assistant general managers, and equipment managers outlining minor changes 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 ball is going to be reduced in weight by less than one-tenth of an ounce. A change in the baseball recently happened in Korea, after they changed the ball size by one gram and moved the COR by .01 to .02. Per the article, slugging in KBO was down 14 percent and homers were cut by a third. I doubt that there will be such a decrease over here, but it shows that the change made an impact.

“When the KBO deadened their ball in 2018, they actually increased the weight by one gram, which corresponded to a size increase of one millimeter, and appeared to substantially increase drag,” points out Dr. Meredith Wills, who has published pieces about recent changes in the ball’s construction at The Athletic and other outlets.

“Unless a decrease in weight can be offset so as not to make the ball smaller, you might expect drag to go down here, leading to the odd situation of a ball that is deader coming off the bat but carries farther. Without greater precision than 1/10 of an ounce (about 2.8 grams, or almost three times the KBO change), any evidence of an aggregate size change could be difficult to detect without a Statcast-sized sample.”

The memo that was mentioned in the report said that an independent lab found that fly balls traveling over 375 feet actually lost one to two feet of batted ball distance with this new ball. Here is some information on how this makes a difference.

For more information, go read the full article in The Athletic (if you have a subscription). We shouldn’t see a major drop in home runs in 2021, but this is definitely something worth noting and something to keep an eye on moving forward.