COOPERSTOWN, N.Y. — The closer role once didn’t exist, then it did, then it was considered something of a gimmick, then it became very important, then not so much and now . . . who the hell knows?

That pretty much sums up the changing game of baseball, the capriciousness of life and why Lee Smith was using a media gathering Saturday as a pulpit to preach the gospel of closing.

“I’ve heard so many guys talk about that [closer] by committee,’’ he said. “Not going to work.’’

The former Cubs reliever will be inducted into the Hall of Fame on Sunday, thanks to his 478 saves and the Hall’s Today’s Game Era Committee, which elected him after he came up short on the writers’ ballot for 15 years. What can’t be argued is Smith’s basic premise — that if closing were easy, there’d be a ton of successful closers.

“I had a lot of guys who were really, really good setup men,’’ he said. “But something about [getting out] that last guy, they couldn’t handle that. To go out there and lose a game in the ninth inning where a guy had just worked his ass off for three hours, and you go out there and screw it up in, like, 10 minutes, that’s a tough thing to get rid of, to get off your shoulders.’’

Especially when your office was Wrigley Field in the 1980s. That meant day games.

“I had some sleepless nights,’’ he said. “The thing with the Chicago Cubs, if I gave up that home run in the eighth inning, ninth inning, and the game’s over at about 4, I see that home run about six times on [TV] before 10. So that thing sort of wears on you, man.’’

This might seem like an odd time to argue about the importance of closers. Smith will be inducted with former Yankees great Mariano Rivera, the first time in Hall history that two relievers are going in on the same day. And with Trevor Hoffman getting inducted last year, it means that the top three leaders in career saves are all Hall of Famers. Smith held the major-league record for saves for 13 years before Hoffman passed him in 2006.

But the closer debate still rages. The numbers people have gotten their hands on the role and have reduced it to a mathematical equation that involves, I don’t know, an isosceles triangle. And they have declared closers not quite as important as they used to be and the save to be almost beneath contempt.

But somebody thinks they’re important. The Cubs, one of Smith’s eight former teams, certainly do. When they traded for closer Aroldis Chapman before the 2016 trade deadline, it was viewed as the final piece of a championship puzzle. The ensuing World Series title made it hard to argue otherwise. And the Cubs thought big this season and signed closer Craig Kimbrel when a lot of teams deemed him too expensive and not important enough.

Don’t even get Smith started on one of the latest trends in baseball: using relievers to start games. What if a manager had asked him to pitch the first few innings?

“It wouldn’t work because I was asleep,’’ he said.

He was laughing and not kidding at the same time. He was known for his ability to take a nap anywhere, anytime, especially during games.

That probably doesn’t help his Closers Are Baseball Players Too argument. But, again, tell that to his 478 saves. And wake him when you desperately need one.

“I remember the stadium in Milwaukee,’’ he said. “The clubhouse was smaller than the one in Chicago. I could actually sleep right in the middle of the floor. The guys would step over me. They were like, ‘Man, how do you do it?’ I’m like, ‘Throw a towel over my face, and I’m out.’

“The trainer’s job was to make sure I was up in the sixth inning. . . . I always was able to relax, and I think that helped a lot.’’

He gets a kick out of the Cubs’ use of wearable sleep-monitoring technology that can help them tell if their players are well-rested.

“Let me tell you what Smitty started,’’ he said. “They got a room in Chicago. It’s like the quiet room. They got beds, and they’re monitoring their sleep.

‘‘I’m like, ‘You’ve got to be kidding! You’ve got to put my name on that door!’ It’s amazing how many organizations have got that where they have a room for the guys to go and relax.’’

Maybe the best thing to say about Smith is that when closers became a big deal, he was the biggest and baddest of them all.

Smith threw hard, and hitters feared him. He did the best with what he had at a time when his role was valued highly.

He was a trailblazer. Also a trail snoozer.

“There was nothing better than waking up with a three-run lead,’’ he said, smiling.