CLEVELAND -- American League All-Star Game starter Justin Verlander told ESPN on Monday that the balls used in Major League Baseball games this season are "a f---ing joke" and that he believes "100 percent" that the league has implemented juiced balls to increase offense.

Verlander, 36, has allowed a major league-high 26 home runs this season. Overall, players hit 3,691 home runs in the season's first half and are on pace to hit 6,668 home runs, which would obliterate the record 6,105 hit in 2017.

Conversations about a juiced ball have percolated since after the All-Star break in 2015, after which home runs spiked. They are up nearly 60% from the 2014 season, and MLB commissioner Rob Manfred commissioned a study to investigate whether the balls were contributing to the home run spike. It concluded the balls were performing differently but didn't attribute a reason. In June 2018, one month after the study was released, MLB bought Rawlings, the supplier of the official major league ball.

"It's a f---ing joke," said Verlander, an eight-time All-Star who is starting his second All-Star Game on Tuesday. "Major League Baseball's turning this game into a joke. They own Rawlings, and you've got Manfred up here saying it might be the way they center the pill. They own the f---ing company. If any other $40 billion company bought out a $400 million company and the product changed dramatically, it's not a guess as to what happened. We all know what happened. Manfred the first time he came in, what'd he say? He said we want more offense. All of a sudden he comes in, the balls are juiced? It's not coincidence. We're not idiots."

Asked if he believed the balls were intentionally juiced by the league, Verlander said: "Yes. 100 percent. They've been using juiced balls in the Home Run Derby forever. They know how to do it. It's not coincidence. I find it really hard to believe that Major League Baseball owns Rawlings and just coincidentally the balls become juiced."

Manfred, who became commissioner in 2015, acknowledged Monday on ESPN's Golic and Wingo the difference in the balls. He has denied any involvement from the league in changing the composition of the ball.

"We think what's been going on this year is attributable to the baseball," Manfred told Golic and Wingo. "Our scientists that have been now studying the baseball more regularly have told us that this year the baseball has a little less drag. It doesn't need to change very much in order to produce meaningful change in terms of the way the game is played on the field. We are trying to understand exactly why that happened and build out a manufacturing process that gives us a little more control over what's going on. But you have to remember that our baseball is a handmade product and there's gonna be variation year to year."