One thing fans of baseball simulation games know are statistics. The whole game revolves around the integrity of the numbers, which is why challenges to those numbers are always a big deal.

That’s why many are questioning the rate at which balls are leaving the parks in 2017.

Actually, it started in the second half of the 2015 season when baseball saw a spike in homers. Speculation began immediately on what could be the cause.

Was it a new crop of home run hitters? Was it the emerging hitting strategy to try to hit more fly balls?

Fans have a long history of trying to figure this stuff out, and for good reason.

Baseball Juiced: Examples of Past Eras

One of the great things about baseball is comparing players in one era to players in another. Or, in the case of simulation games, actually playing, say, the 1927 New York Yankees against the 1996 New York Yankees.

Fans know certain eras are tainted in some ways, and that it’s not exactly apples to oranges when you compare players from some eras with another. Here are two examples.

The Dead-Ball Era. The Dead-Ball Era lasted from about 1900 to 1919, when Babe Ruth changed the game by becoming a great power hitter. The ball before Ruth was softer and typically used until it unraveled, making it difficult to hit far. Pitching numbers during this era are much better than other periods. On the flip side, any player who might have been a fantastic home run hitter never got the chance to show his skills.

Steroids. The period between the 1990s and 2010 brought many steroid-related discoveries, including admissions from home run hitters Mark McGwire and Jose Canseco that they used steroids during their playing days. Alex Rodriguez and Ken Caminiti also admitted to steroid use.

That’s just two examples, but any changes to the players, the ball, the rules or field dimensions always catches fans’ attention.

The Year of the Pitcher

Part of the reason people speculate that the baseball may be “juiced” in some way is that 2014 was another Year of the Pitcher.

Much like in 1968, when pitchers such as Bob Gibson and Tom Seaver dominated, 2014 saw overall earned run averages drop in both the American League and National League. This time around, it was pitchers such as Clayton Kershaw and Chris Sale who dominated.

Then came 2015 and a surge in home runs in the second half of the season – a trend that has accelerated in 2017. At the current pace, more home runs will be hit in 2017 than any year ever.

Fans have asked: why the sudden switch?

Researching the Trend

Both the 538 blog for the New York Times and The Ringer have done research into the issue. Using data analysis, they eliminated many factors, such as weather, strike zone changes, an influx of young hitters, pitchers changing their strategy, or more widespread use of steroids.

They concluded that the ball is the reason. In The Ringer, they noted balls fly farther if:

  • They are smaller
  • The seams are lower
  • The “bounciness” of a ball is increased when it’s slightly harder, among other reasons
  • The exit speed of ball leaving the park indicates that one, some or all of these factors might be in play

They even had baseballs used in games tested at Washington State University. The university found differences between balls used before and after the 2015 All-Star break, included slightly lower seams, more “dynamic stiffness” (a fancy way of saying the ball was harder), a slightly smaller circumference and slightly less weight.

While one of these factors could not affect the number of home runs, in combination they could.

Major League Baseball has said there are not changes in the ball. But the research indicates these slight changes may have led to the recent home run explosion. It’s at least enough to make always-vigilant baseball fans take notice.