MLB's baseball is behaving differently again, but no one seems to know why

New York Times

13-06-2025

Something's up with the baseball. Again.
Deep flies aren't flying as far this year in Major League Baseball, and the league office is acknowledging as much. A review by The Athletic of MLB's publicly available data shows there has been more drag on the ball in 2025 than in any of the other nine seasons that MLB has tracked it. As a result, equally hard-hit fly balls are coming up 4 feet short, on average.
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That indicates that this year's ball is somehow different than last year's, but it's unclear why. When contacted by The Athletic, MLB confirmed the difference in the ball's performance, including the 4-foot reduction on long flies, but did not offer a specific explanation. The league says, though, that no intentional changes were made to the ball for this season.
'For the last several seasons, MLB has made drag information available to the public online, which is updated daily during the season,' league spokesperson Glen Caplin said in a statement. 'We are aware of an increase in average drag this season and have provided information to the Major League Baseball Players Association on this issue as our experts continue to study any potential causes beyond normal variability in a product made by hand with natural materials. There has been no change to the manufacturing, storage or handling of baseballs this year, and all baseballs remain within specifications.'
A potentially tiny change in seam width or height is one theory the league office has identified, according to a league source who was not authorized to speak publicly, but nothing is conclusive at this point. Baseballs are hand-stitched, prompting league officials to point out there will always be some ball-to-ball and batch-to-batch variation. However, something appears to be happening at scale: On all but four individual days this year, there has been more drag on the ball than last season's average.
The mean drag coefficient this year is .3514. The previous high in the Statcast era was .3462 in 2016. That means that something about the ball is causing it to drag more through the air, which would theoretically reduce how far the ball would go.
Some players said they have noticed well-struck balls are no longer leaving the yard.
'I've definitely hit some balls that I thought were gonna have a chance and they've been caught against the wall,' said A's slugger Brent Rooker. 'Maybe the extra drag is why my expected slugging percentage is 100 points higher than my actual slugging percentage.'
In meetings, players have brought the topic up to commissioner Rob Manfred himself. The commissioner acknowledged to players that the ball has performed differently, said one meeting participant who was not authorized to speak publicly about the closed-door conversation.
'The Players Association has been monitoring baseball behavior throughout the season, and recently reached out to the commissioner's office to review available data and request additional information on a range of baseball measures,' said Kevin Slowey, MLBPA's managing director of player services, in a statement.
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MLB's position is that gameplay is largely unaffected. The league said that the results through Monday — which marks the first 978 games, or about 40 percent of the season — are 'in line' with last year through the same amount of games.
'Long fly balls hit at similar trajectories travel about four feet less than they did through this time last year,' Caplin said. 'In terms of outcomes on the field, 2025 remains in line with 2024 results.'
MLB cited three statistics: home runs per ball in play were at 4.2 percent this year, compared to 4.1 percent in 2024; batting average was at .244, compared to .240; and runs per game were at 8.6, compared to 8.7.
The additional drag might be obscured by the fact that MLB batters are hitting the ball a little harder this year overall. At the same time, the missing length on fly balls could be reflected in other stats.
Across 28 of 30 MLB stadiums this year — removing the two minor-league parks that are being temporarily used in Sacramento, Calif., and Tampa, Fla. — home runs as a percentage of fly balls hit in March, April and May are at an eight-year low.
Professor Alan Nathan, who helped come up with the formula for drag on the baseball, and who was on a league-organized commission that looked into the state of the ball back in 2018, said more work is to be done.
'When I correct for air density, using game-time temperature and elevation, I find that the ball traveled about 3.2 feet farther in 2024, with a standard error of about .5 feet,' said Nathan, professor emeritus of physics at the University of Illinois. 'This is more or less what I would expect based on the difference in Cd (drag coefficient) for the two seasons. I would not take this to be the definitive word on the subject, as there is much more analysis one might do.'
The above graph suggests that MLB has, overall, produced a more consistent baseball in recent years. From 2015 to 2019, there were wild year-to-year swings in drag. Over the past few years, however, MLB has bought the ball manufacturer, changed the bounciness of the inner core and installed humidors in every park. The past four-plus seasons have been relatively serene in comparison. Which makes what is happening this year all the more surprising.
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The ballmaker Rawlings, which MLB partially owns, constructs the major-league ball in Costa Rica and the minor-league ball in China. Tariffs have not changed the league's manufacturing or import process, Caplin said.
They could at some point have an impact, however. Manfred acknowledged last week that the league could incur additional costs on ball imports because of the tariffs.
'There are potential tariff costs,' Manfred said in a press conference at MLB headquarters during the league's owners meetings. 'Costa Rica's not much of a tariff problem to be honest with you. The minor league baseball's made in China, that's more of an issue.'
(Illustration: Kelsea Petersen / The Athletic; Photo: Ron Jenkins / Getty Images)