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‘Juiced’ Balls Didn’t Spur Home Run Record, Study Finds

Major League Baseball touted a study Wednesday that clears it of having intentionally juiced baseballs to cause more home runs in the 2019 regular season.

(CN) – Major League Baseball touted a study Wednesday that clears it of having intentionally juiced baseballs to cause more home runs in the 2019 regular season.

Conducted at the Sports Science Laboratory at Washington State University, the league-commissioned study attributes the record 6,776 home runs hit this year “to a change in player behavior rather than to changes in the baseball.” The last record, set in 2017, was 6,105 home runs.

Undertaken by professors Alan Nathan, Jim Albert, Peko Hosoi and Lloyd Smith, the study looked at 65 dozen unused Major League baseballs from 2013 to 2019, with 20 dozen balls from both the 2018 and 2019 seasons. Researchers also studied the drag coefficient and seam height of 20 dozen baseballs from the 2019 postseason. 

They said their findings showed no evidence of the balls being “juiced,” as several players and managers speculated during the 2019 season.

“We have never been asked to juice or dejuice a baseball, and we've never done anything of the sort, never would on our own,” Rawlings President and CEO Michael Zlaket said at a press conference on Wednesday.

Both data from the league’s StatCast database and laboratory measurements showed that “a significant part of the home run increase in 2019 was due to a reduction in the drag properties of the baseball, although some was due to a change in launch parameters.” 

In addition to StatCast’s trajectory data on fly balls, the researchers looked at the data of pitched balls, as well as “the dependence on spin and the relationship to fly ball distance.”

“The StatCast data were analyzed using the technique described by Albert to separate the home run changes into two parts: a part due to changes in carry and a part due to changes in launch conditions,” the 27-page report explains. 

Data showed a correlation between seam height and drag, and the report says the change in seam height from 2018 and 2019 was less than one-thousandth of an inch. 

The analysis also showed that 60% of the home run increase between 2018 and 2019 was due to an increase in carry, while 40% was due to a change in launch conditions.

Of the increase in home run rate, a change in the seam height accounted for just 35% attributable to greater carry, according to the report.

“Whether year-to-year changes in those spin rates play a role in the changes in home run rates is currently under investigation,” the report states.

Using newly developed techniques, the researchers said lab tests showed “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.”

Studies found that Rawlings uses the same manufacturing process to make baseballs for the postseason, so there is “no reason to suspect a change in the performance properties of the baseball between the regular and postseason.” 

The report concludes with recommendations for Rawlings and Major League Baseball. 

“Rawlings should develop a system to track the dates on which balls are manufactured and shipped to clubs,” the report states. “Clubs should log which batches of baseballs are used in which games or homestands.” 

It is also suggested that MLB install “atmospheric tracking systems at field level in all 30 ballparks” as well as humidors to “reduce the variability in storage conditions across the league.” 

The report also calls for a more extensive study of “the apparent dependence of drag.”

“Moving forward, we will continue to work with them as we explore the sources of drag variation in the baseball,” said Chris Young, vice-president of on-field operations initiatives and strategy at MLB. “We do understand, however, that this is a handmade, hand-stitched process, and the use of natural raw materials creates a variability in the baseball performance that is, to some extent, unavoidable. In addition to accepting the recommendations of the committee, we'll remain focused on controlling the sources of variability as best we can, including the mudding application process, the shipment, and the storage conditions.”

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