What’s causing the Major League home run surge?

There’s something odd going on in baseball, or perhaps we should say “going out.”

Thursday night the Dodgers slugged three home runs in a 6-2 interleague victory over the Angels. That brings the Dodgers 50 home runs for the month and an a new all-time record for the franchise.

And it’s not just the Dodgers crushing homers at a record rate.

To date, more than 2,900 home runs have been swatted out of big league parks 2017. That’s on track to shatter the previous high of about 5,700 home runs in a single season that was set in 2000, the middle of baseball’s steroid era.

So what in the name of Babe Ruth is going on?

Part of the answer is lies in changes in the way the game is played. In this era of sabermetrics, home runs are valued more than ever before, and players are encouraged to swing for the fences.

But Ben Lindbergh, a staff writer for the sports web site The Ringer, says that doesn’t adequately account for the elevated home run numbers. He says that, in spite of denials by Major League Baseball, the best explanation lies with the balls that are leaving the yard:

“The ball, post-home run surge, seems to be a little bit smaller, the seams seem to be a little bit lower and the coefficient of restitution, or the COR, which is basically the ball’s bounciness seems to have increased,” Lindbergh says. “That means that not only is the ball being hit harder because of this increased bounciness, but it’s also carrying farther because there is less drag, less air resistance. And so you hit a ball exactly as hard at the same angle as you might have hit it three years ago, and it will carry significantly farther now.”