AP

Justin Smoak's opposite-field drive dropped over the left-field wall in Toronto, and an eye-popping record had been set: Batters reached a home run mark for a month, shattering the syringe-fueled high of the Steroids Era.

Hitters went deep 1,101 times in June, topping the 1,069 of May 2000, according to the Elias Sports Bureau.

"Global warming! The warmer it is, the farther the baseball's going to fly," joked Chicago Cubs manager Joe Maddon.

Humor aside, it became clear that far more than just weightlifting gave batters a lift as the 20th century ended. Offense declined after drug testing with penalties started in 2004 and amphetamines were banned in 2006.

But batters have perked up since the second half of the 2015 season. Four of the top six home-run months have occurred in 2017 or last year, with June joined by this May (1,060) along with last August (1,053) and June (1,012).

"I cannot offer you a concrete explanation for the increase in home runs," baseball Commissioner Rob Manfred wrote Friday in an email to The Associated Press.

"We have tested the baseball extensively and are convinced that is not the answer. We have significantly increased our drug testing and are comfortable that PEDs are not the answer. Given these efforts, I feel that the increase in HRs is attributable to changes in the game and the approach of hitters that have been well documented."

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June's average of 2.70 homers per game also set a mark, topping the 2.64 in May 2000.

"There's a weirdness to this season," Cincinnati manager Bryan Price said. "Everybody throws 100 mph, and everybody hits 24 homers in 60 games."

Baseball offense is becoming all or nothing. Strikeouts have set records for nine consecutive years, with last season's average 8.02 per team per game up 27 percent from the 6.30 average in 2007. This season's average is 8.23, on track for another high.

"The game has turned into more of a max-effort affair on a number of fronts," said Baltimore's Mark Trumbo, who led the major leagues with 47 homers last year. "The home run is in fashion, and I'd say guys are taking their rips at it."

Tampa Bay pitcher Jake Odorizzi suspects a more nefarious explanation.

"I know a lot of times I get balls back, regardless of the result, and there's a dent in them. I just think that's how they changed it and didn't really divulge it to anybody," he said. "But it's kind of a speculation kind of thing until something officially comes out."

MLB has UMass-Lowell's Baseball Research Center test the Rawlings balls periodically. Pryce had a tongue-in-cheek scientific solution.

"We'll weigh it. We'll measure it. We'll saw it in half, and we'll define if it's wound tighter, if there's a magic pill in the middle of it that's making it shoot an extra 40 yards when it's put in play," Price said. "I would think that would be the simplest thing to do."

Aaron Judge, whose major league-leading 27 home runs is two shy of the Yankees' rookie record set by Joe DiMaggio in 1936, maintains video and analytics have titled the balance to batters in recent years.

Clouts have become prized over mere contact.

"Instead of just putting the ball in play, they want to do damage now. They want to hit the ball with purpose, barrel the ball up," the 6-foot-7, 282-pound Judge said.

"There are players emerging on a yearly basis who are just bigger, stronger and faster," Colorado manager Bud Black said.

Judge's drive off Batimore's Logan Verrett on June 11, which cleared Yankee Stadium's left-field bleachers and would have traveled 495 feet unimpeded, is the longest this season.

Chad Pinder hit what was thought to be just the fifth home run into the second deck at Oakland since the level opened in 1996, a May 20 shot against Boston that Statcast pegged at 460 feet.

An emphasis on increased pitching velocity may be tied to power.

"You hit something that's going faster, it's going to exit faster, which in turn causes it to go farther," New York Mets outfielder Jay Bruce said.

Even Clayton Kershaw has been impacted. The Los Angeles Dodgers ace pitcher, regarded by many as baseball's best, has given up 17 home runs this year — one more than his previous high for a season.

"I think guys are fixated on the home runs across the game," Houston manager A.J. Hinch said. "We've seen that change over time, OPS, power, homers, a lot of big swings, very few two-strike approaches, launch angle."

Atlanta's Matt Kemp, who hit 39 homers in 2011, feels left behind. He went deep just twice in June.

"High home run month for everybody else," he said chuckling, "except me."