Just before 10 p.m. on the night of Oct. 6, 2016, the gate to the home bullpen at Cleveland’s Progressive Field swung open, and into Game 1 of the American League Division Series jogged Andrew Miller, the Cleveland Indians’ superb setup man. The Indians’ lead had just been reduced from two runs to one, and the visiting Boston Red Sox had the heart of their order coming up — the perfect spot for Manager Terry Francona to deploy his best reliever.

Only one thing made this scenario seem extraordinary: It was the fifth inning.

With that, a baseball revolution was born — or so it seemed at the time. As Miller mowed down hitters throughout the Indians’ march to the World Series — entering games anywhere from the fifth through the eighth innings, but never the ninth, and delivering anywhere from four to eight outs per outing — fans, pundits and industry insiders alike wondered if they were witnessing a new paradigm for bullpen usage that would change the game.

And some five months later, at the doorstep of a new season, the answer seems to be: not exactly.

“First of all,” Francona said one February morning at the Indians’ spring training headquarters in Goodyear, Ariz., “you have to have an Andrew Miller.”

And so, we will begin this examination of how bullpens are evolving in the second half of the second decade of the 2000s with that simple fact: There is only one Miller, a 6-foot-7, side-slinging lefty who last year held opposing batters to a .193 on-base percentage, essentially reducing every hitter he faced to an opposing pitcher whose only hope was to take three hard whacks in case he hit something.

“Not too many teams have an Andrew Miller,” Oakland A’s Manager Bob Melvin said. “The fact he can go one-plus [innings] is a key. He comes in — let’s say he gets out of a jam, gets one or two outs, and you need him to go another inning. There aren’t too many guys who can do that.”

But even Melvin acknowledged, after watching what the Indians did last summer, “It got a lot of teams, including us, thinking about how to use their bullpen a little differently.”

Even if you do have an Andrew Miller, as Francona does, it doesn’t mean you can simply press a few buttons and revolutionize the way bullpens are run. As Francona and Miller have said over and over since last fall’s pennant run, the unique circumstances of the postseason — short series, higher stakes and most importantly, frequent days off — allow for earlier entrances and extended outings. And those patterns can’t be replicated in the regular season, at least not without risking serious injuries.

“What people forget is, every situation that calls for your best reliever — you have to get him up [ahead of time] to be ready for that situation,” Francona said. “You start doing that in the sixth inning in April, May, June — that [high-leverage jam] goes away more often than it doesn’t. So you sit him back down, and the situation comes up again in the seventh and eighth, too. That guy is going to last about a week, and then he’ll be hurt.”

Looked at one way, Francona’s reliance on his top relievers last fall was a practical solution to a grim problem: The Indians’ starting rotation was perilously thin. To have any chance at all, he was going to have to use his best pitchers as often as possible, which included starting ace Corey Kluber on three days’ rest three times.

“I think they looked at it as: ‘How can we get the most innings out of our best pitchers?’ ” Milwaukee Brewers Manager Craig Counsell said. “So instead of looking at one inning at a time, they found the biggest spots to let those guys go multiple innings.”

What the Indians did, then, was let the concept of leverage — the notion that certain situations are more important than others — dictate their bullpen usage, as opposed to traditional roles. Everyone knows a bases-loaded jam in the eighth inning of a one-run game with the opponents’ 3-4-5 hitters coming to the plate, for example, has more influence on the outcome than a nobody-on, nobody-out situation in the ninth inning of that same one-run game, with the bottom of the order due up.

It’s not as if the Indians were the first team to figure out your best pitchers should pitch in the biggest spots. But over the years the understanding of leverage has come into conflict with the supremacy of the save — the statistic, made official by MLB in 1969, that has come to be the catchall measure of a closer’s performance. Though it does no better in measuring a reliever’s batter-to-batter effectiveness than the win does for a starter, the save became the essential criterion in how relief pitchers are paid, both in the open market and via arbitration.

For most teams, the closer is the best, most trusted reliever, and he almost always gets the ninth inning — where the saves are. In some corners of the game, it remains an entrenched hierarchy.

“Closers are a special breed,” Angels Manager Mike Scioscia said. “ … So if you do use your closer for some reason is on the line in the seventh inning, and ally the best chance for you to control this game — then, yeah, you’re just rolling the dice at the end with guys not really what they have been groomed to do.”

For the Indians to attempt to alter that system, they needed relievers who were willing to believe in leverage over saves.

“Like any human beings, relievers like having some idea of what the expectations are and when you are expected to perform,” said Chris Antonetti, the Indians’ president of baseball operations. “There had to be a willingness to get away from that, to allow variables in, to where it’s not just, ‘You’re pitching this inning. You’re pitching that inning.’

“It’s guys having the flexibility to pitch in different times in the game. Some of the more creative managers are going to take advantage of that. But it also takes communication between the manager, the pitching coach and the players.”

Miller is clearly the Indians’ best reliever, but he is not their closer. That title belongs to Cody Allen, a 28-year-old right-hander who last year converted 32 of his 35 save attempts. (Miller pitched in save situations three times after being acquired in a trade in July and converted them all.) Setup man Bryan Shaw often operated as a right-handed complement to Miller.

“People have been talking about leverage for a number of years. It’s not anything new,” San Diego Padres General Manager A.J. Preller said. “But it only works if you have a quality, deep bullpen. If you have that, you have the flexibility to do those things. You can’t bring in your best reliever in the fifth or sixth inning if you don’t have quality guys behind them. In the Indians’ case, with Shaw and Allen, they were all kind of like pseudo-closers. It enabled e it that way.”

Francona certainly didn’t invent the notion of the high-leverage, multi-inning fireman in the postseason. He wasn’t even the first to use Miller in that role.

In Game 1 of the 2014 ALDS between the Baltimore Orioles and Detroit Tigers, Orioles Manager Buck Showalter brought in Miller — who, similar to 2016 with Cleveland, had been acquired in a trade-deadline deal a little more than two months earlier — to pitch the sixth inning, with the heart of the Tigers’ order coming to the plate and the Orioles ahead by a run. Miller wound up delivering five crucial outs in a Baltimore victory and went on to appear in four more games that postseason, entering in the seventh inning each time.

“I’m not sure how revolutionary this is,” Antonetti said. “Fifty years ago, people knew that a one-run game, bases loaded in the sixth inning — the game may be decided here. It’s not as if we’re inventing something.”

In the end, what the Indians did with their bullpen last October was less of a revolution itself than a symbol of a larger shift within the game. This is the age of the dominant bullpen, in which innings pitched by starters is in decline — from 6.0 innings per start in 1996 to 5.8 innings per start in 2006 and down to 5.6 last season — and seemingly every team has three or four flamethrowers in their bullpen whom they can deploy in succession late in games.

This offseason, three relievers — Mark Melancon, Aroldis Chapman and Kenley Jansen — shattered the previous record for biggest contract for a closer, with Chapman leading the way with a five-year, $86 million deal from the Yankees. Previously, Jonathan Papelbon was the highest-paid closer, with a four-year, $50 million deal. Miller’s current four-year, $36 million deal is the largest ever for a non-closer.

It stands to reason that as teams pour more resources into their bullpens, they will begin to reexamine how those weapons are deployed. It may not be easy to replicate what the Indians did in October, but that doesn’t mean teams won’t try.

“Last year it was clear the trend was, get your starters out early and go to these deep bullpens,” San Diego’s Preller said. “Whether that’s going to be a long-term trend where everyone’s looking to build teams that way — that’s tough to tell at this point. It’s based on your individual club. Some teams, like what you saw from the Indians, felt like they didn’t have the depth of starting pitching, so they felt their best option was bringing in their best relievers early and in big spots.

“Can you do that over the long haul of the regular season? That’s a question that still hasn’t been answered.”

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