Before the Chicago Cubs completed a trade for Aroldis Chapman, owner Tom Ricketts and president of baseball operations Theo Epstein decided they had to hear from the closer himself about a domestic violence allegation in the offseason.

So Ricketts and Epstein asked Major League Baseball for a window to speak with the left-hander, and they got him on the phone Monday. When the conversation was over, the blockbuster deal was on.

Chasing their first World Series title since 1908, the Cubs addressed one of their few weaknesses by sending a pricey package of four players to the New York Yankees for Chapman, one of the most dominant relievers in the game, but one who also comes with some risk for a franchise riding a positive wave.

“This is a game-changer. Aroldis Chapman is a game-changing-type pitcher in the postseason,” Epstein said. “As you sit around and game plan how you’re going to win a big game or how you’re going to win a postseason game, it makes it look a lot easier when you see him there on your lineup card.”

Chapman is expected to join the Cubs for tonight’s game at the crosstown White Sox.

For the Yankees, it was a rare July trade that saw the best player in the deal leaving New York. But Chapman is eligible for free agency after this season, New York also has All-Stars Andrew Miller and Dellin Betances in the bullpen, and its haul included top shortstop prospect Gleyber Torres, versatile pitcher Adam Warren and minor league outfielders Billy McKinney and Rashad Crawford.

“This was an easy call, and this was the right call,” general manager Brian Cashman said. “Easy because we traded from an area of strength and we are excited about the players that we’ve received for someone that obviously was only under control for two more months.”