Giants' Madison Bumgarner on juiced balls in MLB: 'There's no denying it'

Where are the 2010 Giants now?

Tim Lincecum: Living quietly in a Seattle neighborhood



Lincecum sold his $2 million luxury penthouse in Downtown Seattle and moved into a home by the lake in Madison Park, where Lincecum sold his $2 million luxury penthouse in Downtown Seattle and moved into a home by the lake in Madison Park, where he's been living quietly for the past few years. less Where are the 2010 Giants now?

Tim Lincecum: Living quietly in a Seattle neighborhood



Lincecum sold his $2 million luxury penthouse in Downtown Seattle and moved into a home by the lake in Madison Park, where Tim Lincecum: Living quietly in a Seattle neighborhoodLincecum sold his $2 million luxury penthouse in Downtown Seattle and moved into a home by the lake in Madison Park, where ... more Photo: Eric Risberg / AP Photo: Eric Risberg / AP Image 1 of / 28 Caption Close Giants' Madison Bumgarner on juiced balls in MLB: 'There's no denying it' 1 / 28 Back to Gallery

Baseball is in the midst of an unprecedented home run binge. Ever since the second half of the 2015 season, when the home run rate mysteriously spiked with no explanation from Major League Baseball, the number of balls leaving the park has gone up, and up, and up. This year, MLB broke the record for home runs in a season — in mid-September. Previously, the record was set in 2017. Eugenio Suarez has 48 home runs. Jorge Soler has 45. Mitch Garver has 31.

The conclusion reached by a number of informed observers is that something in the ball changed after the 2015 All-Star break. This change produced a ball that flies further than the previous balls. This is colloquially being called a "juiced ball." MLB commissioner Rob Manfred says MLB has not knowingly altered the ball, saying that he thinks the manufacturers are doing a better job at "centering the pill," whatever that means.

The San Francisco Chronicle spoke with Athletics reliever Blake Treinen as well as Giants starting pitchers Jeff Samardzija and Madison Bumgarner on Friday about the changes in the baseball. Their conclusion? That ball is juiced.

"There's no denying it," Bumgarner told the Chronicle. "I don't think anybody at this point is denying the ball is different. It's definitely different, and it's affecting a lot of the all-time stats."

Does Bumgarner like it? No, he does not.

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"I just don't like it when they change the game so much," Bumgarner said. "This changes it a lot."

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As the Chronicle points out, other variables may be affecting the spike in balls leaving the park. In Ben Lindbergh and Travis Sawchik's excellent book "The MVP Machine," the two authors reported on the rise of MLB players working with independent hitting instructors to adjust their swing plane upward. This trend may explain some of the home run increase.

But not all of it. As Lindbergh and Rob Arthur noted in a 538 story from 2017, the sudden spike between the first half of the 2015 season and the second half of the 2015 season rules out any larger structural changes, and points to a singular explanation: the ball is juiced. Bumgarner, not one to complain without justification, seems to agree.

Michael Rosen is an SFGATE digital editor. Email: michael.rosen@sfgate.com