If it feels like you’ve seen a lot of home runs in 2017, it’s because you have: We have a new major league record for home runs in one season.
The record-setting blast came courtesy of Kansas City Royals outfielder Alex Gordon, who took Toronto‘s Ryan Tepera deep in the eighth inning on Tuesday for the 5,694th home run in the majors this season, breaking the previous record set in 2000.
There were 5,610 homers last year, an average of 2.31 per game. And this year’s average of 2.53 entering Tuesday’s action projects to 6,139.
That’s a dramatic increase from just a few years ago, when everyone was suddenly worried about the lack of power in the game. In 2014, there were just 4,186 home runs hit, the fewest in a non-strike season since 1993, when there were 28 teams instead of the current 30.
Entering Tuesday’s games, players were hitting an average of 2.53 home runs per game, well above the record of 2.34 in 2000.
The uptick in home runs began in the second half of 2015 and led to much speculation as to what has caused the barrage of home runs. The most plausible explanation is a change in the ball. Ben Lindbergh of The Ringer and sabermetrician Mitchel Lichtman found that the balls became smaller and the seams got lower — changes that would make the ball smoother and subject to less air resistance. Rob Arthur of FiveThirtyEight.com had findings that expanded on that, noting that there has been a significant decrease in the air resistance, or drag, of the ball, which has led to an increase in fly ball distance and, therefore, more home runs.
MLB has denied any alterations to the ball, but even small changes in the manufacturing process could alter the ball while keeping it within the range of acceptable measurements.
Compared to 2000, more power is coming from the bottom of lineups. In 2000, 16 players hit 40-plus home runs. This year we have just three. That Gordon hit the record-setting homer on Tuesday was notable: The No. 9 hitter in the Royals’ lineup, he entered the day with a .307 slugging percentage, lowest in MLB among those qualified for the batting title, according to ESPN Stats & Information research.
This season already has set records for the number of players with at least 10 home runs and 15 home runs; and a new record for 20-homer seasons is in sight. In 2014, there were 57 players with 20-plus home runs; entering Tuesday, there were 108 (the most was 111 in 2016).
Rookies have also been major contributors, led by Aaron Judge, who had 44 home runs entering Tuesday and who has a chance to break Mark McGwire’s rookie record of 49 set in 1987. Rookies had hit 708 home runs entering Tuesday, the most ever and nearly twice as many as rookies hit in 2000. With 38 home runs entering Tuesday, Cody Bellinger was tied for third-most ever by a rookie.
Besides Judge and Bellinger, Giancarlo Stanton has dominated the home run highlights, with 55 entering Tuesday. Stanton has a chance to become the first player to reach 60 since Barry Bonds and Sammy Sosa in 2001. Stanton belted 18 home runs in August, becoming the third player to hit 18 in a calendar month (Sosa had 20 in June 1998, and Rudy York had 18 in August 1937). He also joined Bonds as the only players to hit 30 home runs in fewer than 50 games.
Information from The Associated Press was used in this report.