Baseballs are flying out of the ballpark at an unprecedented rate in the 2017 season. At the All-Star break, 24 total players have hit 20 home runs or more. Compare that with the 2014 season when only 47 players hit 20 or more homers in the entire season, and we can clearly see a shift. According to the Washington Post, 14.2% of all hits so far in 2017 have been home runs — the highest rate in Major League Baseball history. The home run to batted ball rate has spiked in a way that we’ve never seen before.

So what about “juicing the baseball?” This is the phenomenon where Major League Baseball alters the balls used in games in a way that leads to move offense or home runs. Is this what’s happening? We took a brief look at the theory, as well as the history of the trends in offense and home runs.

1. The Dead Ball Era

First, there was the Dead Ball Era. This was a period in the early 1900s when home runs and offense were both at a minimum. For example, the 1913 Philadelphia Athletics were by far and away the best team in baseball. They finished 96-57 and won the World Series, but did so by hitting 33 total home runs. The team was No. 1 in the American League in slugging percentage, but at a paltry .375.

In those days, the baseball was softer and even slightly large. A softer, larger ball was harder to hit, meaning home runs were more scarce. This is a solid explanation for why pitchers were so good at getting outs without striking out batters; those same Athletics posted a 3.19 ERA as a team, despite striking out just 4.2 batters per nine innings.

2. The “Second” Dead Ball Era

There was a second Dead Ball Era around baseball, running for about eight years from the mid-1960s through the early ’70s. Some people debate whether this was a true “Dead Ball Era” or if there was merely an extended period of time when quality pitching outweighed the hitting around the game. The downgrading of the level of offense certainly wasn’t the same as in the early 1900s, when home runs were extremely infrequent.

But the league batting average in 1968, for example, was just .230. Compare that with 2017, when the average around baseball is a much more healthy .255. This era helped lead to the advent of the designated hitter in the American League, or a batter who specifically replaces the pitcher in the lineup without playing in the field. Offense kicked back up again in the ’80s.

3. The rise of the “juiced ball”

In the ’80s came the first real talk about the “juiced ball.” Back in 1987, home runs ticked up and the attention turned to the “rabbit ball,” or the nickname players used for how the ball used to jump off the bat. For example, six players hit 40 or more home runs during the entire decade and four of them came in the ’87 season. The number of players to hit 20 or more home runs ticked up that year as well, with 79 of them around baseball. Again for comparison, only 60 hit 20 or more home runs in 1986 and only 45 did it in 1988.

Bobby Bonds, who was 41 years old and retired in ’87, had this to say about the rabbit ball:

I’ve taken batting practice and I’ve hit those balls… I’ve hit the ball as far as I did when I was 25 years old. I’m not that strong. I hit balls really terrible and they go over the fence. When I was playing, I’d hit balls and say, “Oh my God,” and it didn’t go out. Now I hit balls and I say, “Oh my God,” and they clear the fence by 30 feet. All the tests can’t convince me. I don’t need tests on some machine. I go by contact.

4. The Steroid Era

The Steroid Era came around in 1998, with “juicing” bringing a whole new meaning in relation to baseball. Players were bigger, and home runs went further and further. Sammy Sosa of the Chicago Cubs and Mark McGwire of the St. Louis Cardinals were at the forefront, chasing down 62 home runs in the summer of ’98. But they weren’t the only ones involved.

Brady Anderson of the Baltimore Orioles broke his career-best of 21 homers with 50. Luis Gonzalez of the Arizona Diamondbacks hit 57 in 2001. Texas Rangers first baseman Rafael Palmeiro hit an average of 43 per season from 1998–2003, when his age ranged from 33–38. And then Barry Bonds crushed 73 homers in 2002.

But the Steroid Era came to an end, with players such as Bonds, Sosa, McGwire, and Palmeiro being discovered and ostracized for their roles in it all. Offense began to dwindle around baseball over the next decade.

5. Has the juiced ball returned?

Back in 2014, MLB players hit 4,186 home runs in the course of the entire 162-game regular season. The average ERA from a pitcher was 3.74, and the Kansas City Royals went to the World Series despite hitting just 95 homers as a team — the lowest in the league. But offense is steadily rising, with the average ERA in 2017 sitting at 4.35 as of the All-Star break. With less than 90 games checked off the schedule, the number of home runs hit is 3,343. That’s a pace of over 6,000 home runs this season.

Of course, that returns the conversation to juiced ball. Some say that the baseballs are wound tighter this year. The seams on the ball are lower. Baseballs hit off the end of the bat travel further, even clearing the fence for home runs.

But in a 2016 report on the rising offense and the performance of the baseballs, the following was found: “There is no evidence from the results of this study that the performance of the 2016 regular-season baseballs… would have resulted in any difference in on-field performance from those used during recent seasons.”

6. MLB makes a statement, and players remain unconvinced

Part of this may be the fact that hitting the ball in the air is better for the hitter. According to FanGraphs, fly balls carry a higher wOBA (Weighted On-Base Average) of around .335 than ground balls (.220). As a result, players may change their swing to intentionally hit the ball in the air more frequently. We can see one clear example with San Diego Padres third baseman Ryan Schimpf: He hits for a very low average but has the most extreme fly ball rate in recent baseball history.

But not everyone believes that the rise in home runs simply involves batters attempting to get more lift on the ball. Major League Baseball sent out a memo to all 30 teams explaining that the ball was no different than in years past, but they still haven’t convinced everyone.

“We’ve got the smallest guy in the major leagues (Jose Altuve) going backside at the Rogers Centre,” (Astros pitcher Dallas) Keuchel said. “You could make a case for, yes, they’re juiced, or no, they’re not. Nobody’s going to know. I personally think sometimes they are.”

All of this could be cyclical. We could encounter another break in the offense in just a few short years. And it doesn’t seem to be much of a coincidence that spikes in home runs seem to come around every 10 years or so. But arguing — about whether there have been changes made to the baseball, the way the players swing the bat, or the players themselves — will always be a part of the game. We don’t ever get real answers, and when we do it only makes us ask more questions.

Statistics courtesy of ESPN and Baseball -Reference.