Early home-run explosion has some thinking the baseballs might be juiced again

The baseball season is still young, but the home run is back. And if early research is any indication, it’s not just the Los Angeles Dodgers who are solely responsible for 2019’s home-run surge. It might be the balls ... again.

[It’s still not too late to join or create a 2019 Yahoo Fantasy Baseball league]

Robert Arthur of Baseball Prospectus used pitch-tracking radars in Major League Baseball parks to determine the aerodynamics of the baseball during the first week of the 2019 season. What he found was that the ball’s drag was really low.

What does that mean? If it keeps up, fans are looking at yet another home-run explosion.

Arthur was one of the analysts who analyzed the ball in 2017. What he found back then was that that the ball’s drag had changed. That’s a big deal. Even the smallest difference in drag can lead to a massive increase in home runs, as Arthur explains:

“[D]rag is incredibly important in determining how likely a hitter is to knock one out of the park. As baseballs become more aerodynamic, they travel further given a certain initial velocity. A deep fly ball that might have been caught at the warning track can instead go into the first row of the stands. A three percent change in drag coefficient can work to add about five feet to a well-hit fly ball, which can in turn increase home runs league wide by an astounding 10-15 percent.”

That small change in drag led to MLB teams shattering the major-league record for home runs in a season. There were 6,105 home runs hit in 2017. The previous record had been 5,693. The issue appeared to be corrected in 2018, when 5,585 home runs were hit.

In 2017, the league denied the ball had an impact on the home-run surge. Commissioner Rob Manfred consistently said the balls were being manufactured within MLB’s acceptable range. Many pointed out that the league’s acceptable range was too large, and that even minute changes to the ball could drastically impact the game.

Major League Baseball eventually commissioned a study which determined the ball had an impact on the extreme home run total in 2017.

Aaron Judge Yankees.
Aaron Judge might be able to feast on baseballs even more than usual in 2019. (AP Photo/Julie Jacobson)

Arthur cautions that there are factors that could make his data inaccurate. If radar tracking has changed, that would throw off his analysis. He spoke to some people within baseball who gave him no indication things have changed.

He also admits that the season is young. Some teams have only played six games. That’s not a huge sample over the course of a full season, though there have been over 5,000 fastballs thrown this season, which isn’t nothing.

Based on this data, Arthur concludes the first week of the 2019 MLB season has been similar to the numbers seen in 2017. And if you just compare April of both seasons, 2019 has seen a higher home run to fly ball rate during the month.

Does that mean the home run record will be broken yet again? Not necessarily. But given what Arthur has found, it’s probably worth picking up that weak-hitting middle infielder who clubbed three home runs over the weekend in your fantasy league and hoping the trend continues.


Chris Cwik is a writer for Yahoo Sports. Have a tip? Email him at or follow him on Twitter! Follow @Chris_Cwik

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