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

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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.

 

Video: Cubs score run on Pirates’ appeal throw

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2019 has been one long nightmare for the Pirates. They’re in last place in the NL Central, have had multiple clubhouse fights, and can’t stop getting into bench-clearing incidents. The embarrassment continued on Sunday as the club lost 16-6 to the Cubs, suffering a three-game series sweep in Chicago.

One of those 16 runs the Pirates allowed was particularly noteworthy. In the bottom of the third inning, with the game tied at 5-5, the Cubs had runners on first and second with two outs. Tony Kemp hit a triple to right field, allowing both Ben Zobrist and Jason Heyward to score to make it 7-5. The Pirates thought one of the Cubs’ base runners didn’t touch third base on their way home. Reliever Michael Feliz attempted to make an appeal throw to third base, but it was way too high for Erik González to catch, so Kemp scored easily on the error.

The Pirates lost Friday’s game to the Cubs 17-8 and Saturday’s game 14-1. They were outscored 47-15 in the three-game series. According to Baseball Reference, since 1908, the Pirates never allowed 14+ runs in three consecutive games and only did it two games in a row twice before this series, in 1949 and in 1950. The Cubs scored 14+ in three consecutive games just one other time, in 1930.