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For much of the past half-decade, Major League Baseball has been flooded with new data, influencing how the game is played and run. This season, that information has put a focus on the sport’s most fundamental piece of equipment: the ball.
From its production to its functionality, the ball has emerged as both cause and symptom of a historically slow offensive start to the season, leading to accusations and conspiracy theories. Through the season’s first month, major league hitters have a combined .233 batting average, the lowest since 1968, and a .629 OPS, the lowest since 1981. Hitters shake their head as they watch high flyballs drop in front of the wall during batting practice. Pitchers grumble about their inability to get a grip – some more publicly than others.
“I’m hesitant to say it’s a big deal because if everybody has to deal with it, you’re like, well, everybody is on the same level of having to deal with it,” veteran reliever Collin McHugh said. “But I would like to not have to, every pitch, see what the ball feels like, decide whether I can throw the pitch I want to throw with it, whether I should try to get a new ball.”
Generations of big leaguers have played with baseballs that are sewn by hand with leather that is a product of its own distinct environment. The baseballs have never been identical. But thanks to the widespread availability of spin rate, exit velocity and ball flight data, this generation of big leaguers knows exactly how much those inconsistencies impact performance.
If the seams are lower than usual and a pitcher snaps off a curveball with a slightly lower spin rate than average and that curveball gets hit, was it the pitcher? Or was it the ball? How much should a pitcher be expected to adapt to the ball versus working around it?
And if small changes to the baseball can affect performance, and MLB is in a position to control small changes to the baseball . . . well, what once felt like a quirk – like different dimensions from one park to another or the preferences of umpires – starts to feel like a bug. Players have floated everything from the league altering balls to decrease free agent earnings to the league juicing them for the sake of more exciting nationally televised games, all charges league officials deny.
But several veteran pitchers say that while fastballs slipping up and in often start these conversations, they are not the most regular issue that arises from inconsistent grip. They argue that slightly higher seams or a slightly chalkier surface forces them to make adjustments hitters don’t have to.
In the first month of the season, 10.3% of flyballs traveled for home runs, the lowest percentage since 2014. And while a shortened spring training limited how much hitters could work on timing and expanded April rosters meant more at-bats against fresh relievers, that little white sphere with the red seams remains at the center of debate.
This kind of talk used to be whispered in the years after MLB bought its ball manufacturer, Rawlings, in 2018. It grew louder when home runs spiked in 2019, then again when MLB confirmed it had made changes to the baseball ahead of the 2021 season, then admitted it had used two different balls because of production issues caused by the pandemic.
Those issues are resolved now, according to a league official who requested anonymity to speak candidly about the league’s efforts. That official explained that the league reworked the baseball before the 2021 season so that it would have a lower and more consistent coefficient of restitution, or COR. The COR refers to the amount of energy lost during impact. The higher the COR, the bouncier the ball.
And while the baseballs the league used in 2019 and 2020 had a COR that was within the range specified in the rule book, they were averaging a number in the high end. In 2018, 12.7% of flyballs ended up as home runs. In 2019, that rate had grown to 15.3%.
Beyond measuring COR, Alan Nathan, a University of Illinois physicist who has previously advised MLB on baseballs, studied drag – the force that works opposite the flight of the ball, caused by the way air moves around the seams and surface. Nathan studied home runs hit between April 18 and April 22 and concluded that the 2022 baseball experiences more drag in flight than it did in April 2021, in 2019 or 2018. The balls are not only less bouncy this season, but also less aerodynamic.
But MLB officials insist that consistency, more than any dogged manipulation of on-field outcomes, has been at the heart of decisions about the ball in recent years.
Before this season, MLB’s home run committee suggested installing humidors – climate-controlled closets, basically – at all 30 parks. The goal was to standardize not only the way the baseball traveled, but also the tackiness pitchers felt while gripping it. The league mandated that 29 of its 30 teams install humidors in their stadiums and set them each to 57% humidity and 70 degrees. The exception was in Colorado, to account for its altitude.
Each humidor holds about 2,400 baseballs, stored in boxes labeled with the dates on which each was placed on the shelf. Balls must stay there for two weeks before they can be used for play.
But even consistent storage can’t stave off other variables, and so far, the humidors have created a slightly wetter baseball that is not traveling as far. The more humid the baseball relative to the air through which it travels, the shorter its flight will be. Early in the season, when the weather is cold and the air relatively dry around the country, that flight has been more limited than in past years.
League officials say they expected ball flight to dip early in the season, but that they also expect to see a change as weather warms and air grows more humid.
Meredith Wills, who has a PhD in astrophysics and has been studying MLB’s balls for years, said she isn’t sure that more humid nights will restore what looks to be a very dead ball to average flight. She said she thinks the changes the league made to the ball with the intention of creating greater consistency in the COR may have created inconsistency in other areas.
“I suspect what we might be seeing with this dead ball and the 2019 ball and all the things that happened since MLB bought Rawlings is this,” Wills said. “One of the best ways to break something is to try to fix something that wasn’t broken to begin with.”
Pitchers, meanwhile, do not seem nearly as worried about how far the ball will fly in April versus June. Their definition of a consistent baseball is one on which they can get a consistent grip, with seams at predictable heights and mud applied uniformly.
Grip has been in the spotlight since the league cracked down on the use of sticky substances last summer, limiting players to the use of a now-standardized Honduran rosin and their own sweat. While pitchers around the game agree that some of their colleagues had simply gone too far with sticky substances, many pitchers express frustration about the lack of tack now on the surface of baseballs.
After watching his teammates get hit by errant pitches 19 times in the first few weeks of the season, Mets starter Chris Bassitt blamed MLB for what he called “slippery” baseballs, suggesting that absent some kind of stickier substance, pitchers cannot grip baseballs safely with rosin alone. Bassitt, who currently has a 2.61 ERA with the best strikeout-to-walk ratio of his career, seems to be overcoming that issue just fine. Leaguewide, hit-by-pitch numbers were down through the first 25 games of the season.
But the question of consistency becomes central to pitchers in different ways. Some pitchers are affected by having to make those adjustments more than others. Veteran Baltimore Orioles starter Jordan Lyles explained that his target changes entirely based on the way the ball feels in his hands. If he wants to throw a curveball, but the seams feel low or the ball feels slippery, he aims much lower.
“If you throw it like a normal curveball, it slips and it will go higher,” Lyles said. “Sometimes you end up less confident in your breaking balls and lean on fastballs. So hitters will stop worrying about breaking balls and just sit on the fastball because they know a guy doesn’t know where the breaking ball is going.”
Adjustments are part of the game for pitchers, and always have been. But what they want, he and others say, is to have to make fewer.
“Hitting is the hardest thing to do in sports. No question,” McHugh said. ” . . . but it feels antiquated to me. Like, do we not have a better fix for this?
“What if they just told hitters you’re not allowed to use batting gloves anymore. They’d be like, what do you mean?”
MLB argues that unlike sticky substances, batting gloves were never against the rules in the first place. But the league is trying to address the grip question anyway.
Multiple pitchers suggested a more standardized process of rubbing the balls with mud before use, and MLB has seemingly begun trying to embrace that suggestion: Instead of having to complete the process a few days ahead of time, the baseballs now must be mudded the day of the game.
Similarly, the sport is testing out a pre-tacked ball in the Texas League, the second recent attempt at a prototype to help meet pitchers halfway. If that ball is well-reviewed and big leaguers decide they like it, too, it could arrive as soon as 2023 – but pre-tacked balls introduce new variables, too.
Changing the surface of the baseball might change its flight. And even if it doesn’t, hand-stitched balls mean hand-stitched seams: Optimizing consistency will never mean complete uniformity. But in the age of data-driven baseball, the goal is always to inch closer to perfection, even in a sport that so rarely allows it.
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