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A second study confirms that home runs are up due to a change in the baseball


Two weeks ago Ben Lindbergh and Mitchel Lichtman released their study at The Ringer which convincingly argues that changes in the composition and construction of the baseball is responsible for the dramatic spike in home runs we’ve seen since the middle of the 2015 season. Yesterday their work was corroborated.

Rob Arthur of FiveThirtyEight, who had last year conducted a study with Lindbergh which proved inconclusive on the matter, has revisited the baseballs as well. Specifically, he used baseball’s data with respect the speed of the ball when it is released from a pitcher’s hand and when it crosses the plate and, based on the loss in velocity in that short period, calculated the ball’s drag coefficient. From that he could compare the drag on the ball from before mid-2015 and the drag since mid-2015.

His conclusion: there has been a significant decrease in the drag on baseballs over the past two years and that decreased drag can account for about five feet of carry on a given fly ball. That, in turn, would account for a 10-15% spike in home runs on average, and a bigger spike in any given month depending on other factors. Arthur:

It’s highly unlikely that we’d see that kind of difference by chance without a real change to the ball: The monthly variation in estimated drag coefficients in the past five seasons varied from around 0.34 to 0.355, a far wider range than we’d expect from random variance alone. In total, the practical effect of shifting from a high-drag month to a low-drag month could be around a 30 percent difference in home run rates.

Arthur cautions us not to become conspiracy theorists here. The change in the ball need not be nefarious as even small alterations in the manufacturing process could lead to these changes. At the same time, he reminds us, that we should ignore MLB’s statements that the balls still fall under the league’s manufacturing requirements and performance parameters, because those parameters are quite broad and allow for these significant variations in ball flight. Even if no one is intentionally doing this and even if the balls are officially up to snuff, they can nonetheless have changed significantly and are the likely culprit for the dramatic home run spike.

Stepping back from the research, this makes a lot of sense. As we’ve noted in the past, there is a long and rich history of changes — even slight changes — to baseball composition leading to dramatic increases and decreases in offensive levels. The dead ball era ended, in large part, because different wool was used beginning in 1919. The National League changed balls in order to intentionally boost offense in 1930 and it worked almost too well. There was a change of baseball manufacturers in the late 1970s which led to a mini spike. 1987 was the year of the so-called “rabbit ball.” That was never fully explained, but there are strong suspicions that Major League Baseball messed with the ball that year.

Other factors matter — new parks with shorter porches, batters making a point to swing with an uppercut, diluted pitching, PEDs, etc. — but none are as significant as changes to the ball itself and none account for the almost immediate spike in homers in the middle of the 2015 season.

Anyway, enjoy the dingers. They’re here to stay. Or at least until the baseballs change again.


Astros exemplify the player-unfriendly bent of analytics

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Even as recently as a decade ago, Sabermetrics was a niche interest among baseball fans. As various concepts began to gain acceptance in the mainstream, players slowly began to accept them as well. Players like Brian Bannister and Zack Greinke were hailed as examples of a new breed of player — one who marries his athleticism with the utilization of analytics. This year, much was made of certain players’ data-driven adjustments, including Daniel Murphy and J.D. Martinez. Both had great seasons as a result of focusing more on hitting more fly balls instead of ground balls and line drives.

Statistics can clearly benefit players. They can also be used against them, and not just by opposing players. The Astros, who are in the World Series for the first time since 2005, are a great example of this. The Astros spent a few years rebuilding after a complete overhaul of the front office, which included bringing in analytically-fluent Jeff Luhnow as GM after the 2011 season. That overhaul instilled so much confidence that, in 2014, Sports Illustrated writer Ben Reiter predicted that the Astros would win the 2017 World Series. He’s only four Astros wins away from being proven correct.

The Astros’ front office, though, took advantage of its players at various times throughout the process. Their success is owed, in part, to exploiting its players. On Twitter, user @chicken__puppet chained a few tweets together exemplifying this:

At its core, analytics is about optimization: getting the most bang for your buck. If you read Moneyball, you know this. Wins Above Replacement (WAR) quickly became synonymous with the field and $/WAR was a natural next step. Sabermetrics defaulted to ownership’s perspective, so highly-paid players who performed poorly were scorned. Cheap players who performed well were lauded.

It is no mere coincidence that once most front offices installed analytics departments, teams stopped handing out so many outrageous contracts to free agent first baseman/DH types. Instead, teams focused on signing their young players to long-term contract extensions to buy out their arbitration years ahead of time, ostensibly saving ownership and the team boatloads of money. Teams began to pay close attention to service time as well. Service time determines when a player becomes eligible for arbitration and free agency, so teams that are able to finagle their players’ service time can potentially delay that player’s free agency by a year. The Cubs tried to do this with third baseman Kris Bryant in 2015, as Craig wrote about.

There is a very real ethical component to covering and being a fan of Major League Baseball, despite the common plea to separate sports from politics. The Astros and Cubs aren’t the only ones exploiting their players; the Angels, for example, made some odd personnel choices earlier this season that happened to allow them to avoid paying some players incentive bonuses. Every front office, in one way or another, games the system because the system is set up to benefit ownership first and players second. And if the likes of Jose Altuve and Carlos Correa can be taken advantage of so freely and openly, what hope does anyone else have?

Fans have been conditioned to group players and owners together as one group of rich people. In reality, the player earning $30 million has more in common with the office worker making $35,000 a year than with team owners. When fans hear about Correa making $507,500 instead of $550,000, or about free agent who wants a nine-figure contract, they wonder why he had the nerve to ask for so much money in the first place. We praise players, like Cliff Lee, who “leave money on the table.” Both the player and that fan, by virtue of existing and participating in this system, are locked in an eternal battle with those who cut their paychecks. Regardless of salary differences, the player deserves to benefit from the fruits of his labor as much as the office worker. Part of being a baseball fan should also include rooting for the players’ financial success and not just the owners’.

Praising the Astros for being smart and savvy will only create more incentive for other front offices to mimic these unethical behaviors. The whole theme of the World Series shouldn’t be about smart, analytically-inclined teams reaching the summit; it should in part be about teams getting ahead with a multitude of exploitative practices against their players.