"He would've been gone 10 years ago if George was still around," Gossage said of Cashman, per Amara Grautski and Mike Mazzeo of the New York Daily News. "He'd have been gone when he jumped out of that f--king airplane. Do you think he's a good f--king baseball guy, really? He doesn't believe in f--king coaching."
He wasn't done there.
"Well, with power, is that what happens to you, you turn into a f--king assh--e. Is that it? I don't know."
Gossage also didn't approve of the team's managerial switch this offseason, when it went from Joe Girardi to Aaron Boone.
"[Cashman] had a good manager in Girardi. They wouldn't let him manage," he said. "They want you to manage the way they want to manage. And he can get one of his nerds in the front office and put him into the dugout. If he had any balls, that's what he'd want to to do, but he doesn't have any balls."
Gossage added that he tried to discuss his frayed relationship with Cashman last year.
"'We used to get along. I used to like you. And then something changed,'" Gossage said he told Cashman. "He didn't answer. He didn't say a word."
Expletive-laced rants aren't out of character for Gossage, who was inducted into the Hall of Fame in 2008 after accumulating 310 saves and being selected for nine All-Star Games over 22 seasons.
In 2016, for instance, he blasted Jose Bautista after he infamously flipped his bat in Game 5 of the American League Division Series between the Toronto Blue Jays and Texas Rangers. Yoenis Cespedes, sabermetricians and Ryan Braun didn't escape his ire either.
"Bautista is a f--king disgrace to the game," Gossage said, per Andrew Marchand of ESPN.com. "He's embarrassing to all the Latin players, whoever played before him. Throwing his bat and acting like a fool, like all those guys in Toronto. Cespedes, same thing."
"I'll tell you what has happened, these guys played rotisserie baseball at Harvard or wherever the f--k they went, and they thought they figured the f--king game out. They don't know s--t.
"A bunch of f--king nerds running the game. You can't slide into second base. You can't take out the f---ing catcher because [Buster] Posey was in the wrong position and they are going to change all the rules. You can't pitch inside anymore. I'd like to knock some of these f--kers on their ass and see how they would do against pitchers in the old days.
"Ryan Braun is a f--king steroid user. He gets a standing ovation on Opening Day in Milwaukee. How do you explain that to your kid after throwing people under the bus and lying through his f--king teeth? They don't have anyone passing the f--king torch to these people.
Gossage was serving as a guest instructor for the Yankees at spring training last year when he made those comments. It's possible Cashman didn't want the Yankees connected to any controversial opinions Gossage might express this year and hence decided against inviting him back as an instructor.
So Cashman became the target for Gossage instead.
"You'd have to ask Cash what the deal is with him," Gossage concluded. "I spoke my mind. But you can't do that anymore."