Home runs, home runs and more home runs. That’s what this MLB season has brought to us so far.

A year after the Kansas City Royals captured a World Series title thanks to an unhittable bullpen, baseball’s offense is producing in a way that hasn’t been seen since the steroid era.

In 2016, MLB hitters have connected on more than 5,420 homers already, the highest total since 2004 when 5,451 home runs were hit. With six games left in the season for most teams, this number only stands to increase.

Last season, MLB players only hit 4,909 home runs. 2014 saw only 4,186 home runs.

Major League pitchers seem to be concerned about the rise of home runs in the game.

“You don’t see year-to-year jumps like this,” Nationals’ pitcher Max Scherzer told ESPN. “Usually, everything stays within itself unless something drastic happens, like moving the fences in around the league, and that didn’t happen.”

After the 2014 MLB season saw the lowest average offensive output since 1992, 2015 saw a slight uptick in offense and 2016 might as well be a complete aberration at this point due to the incredible improvement in offense.

The 2014 season league average OPS (on-base plus slugging) was .700. Two years later, the average OPS is .739, a remarkable increase and the highest since 2009.

Players who aren’t supposed to be hitting home runs are leaving the yard at a blistering pace. In 2014, only 57 players hit more than 20 homers. This year, an astounding 103 players have hit 20 or more homers.

One of the more peculiar players to launch 20 or more home runs this year is Philadelphia Phillies shortstop Freddy Galvis. In four seasons before the 2016 season, Galvis only managed 20 home runs combined. In fact, the most he ever hit in a single season was seven. That’s it.

This year, Galvis has smacked 20 homers, doubling his career total in the process. While he does carry an unimpressive slash line of .243/.275/.402, his home run output is valuable for the shortstop position.

To put things into perspective, only three shortstops in the entire league hit 20 home runs in 2014. This year, 12 shortstops have already accomplished that same feat.

Brian Dozier hit 42 home runs this year, breaking the previous record of 40 home runs hit by a primary second baseman. Dozier is known for his power, but his previous season-high home run total was only 28.

Players who aren’t known for their power are hitting a bunch of home runs, and players who are known for their power are also hitting a bunch of home runs. Basically, everybody in baseball right now is hitting more home runs than we’ve seen in the past 10 years.

What’s responsible for the rise of offense this season?

Before jumping to the conclusion that players have been sneaking steroids past the MLB, there are much more reasonable explanations.

Throughout baseball history, hitters and pitchers have always adjusted to each other. The past several years have been dominated by pitching, as MLB hitters struck out 37,446 times in 2015, an all-time record. This narrowly edged out 2014, which had 37,441 strikeouts.

Maybe this is the year hitters are finally starting to adjust and counter pitching dominance. Walk rates have risen considerably this year, and while strikeouts are up, that may just be a side effect of the major power increase across all of baseball.

Some have also been suspicious of the actual baseball itself. Shortly after MLB Commissioner Rob Manfred took over for Bud Selig at the beginning of 2015, he lobbied for more offense in the game. In the time since, home runs have increased significantly.

In a data package proposed by the MLB to the player’s union in 2015, it suggested “wrapping the ball tighter to make it fly farther.”

While there is no evidence this ever happened, it certainly raises questions as to if there is an actual, legitimate reason that offense is up in baseball or if this year is simply an anomaly.

Whatever the reason may be, the game of baseball has had an infusion of offense this season. In a time that the game is struggling to attract younger viewers, home runs and more offense can only help the game at this point.