In an age when everything on a baseball field can be quantified and culled into scouting reports that reveal the strengths, weaknesses and tendencies of pitchers and hitters, it’s almost refreshing to come across an old-school approach like that of Dodgers reliever Blake Treinen.

“The biggest thing for me is just getting ahead of guys, honestly,” said Treinen, a 36-year-old right-hander whose late-season dominance helped fuel the team’s run to the National League Championship Series against the New York Mets.

“I mean, it sounds so simple, but as much as the game changes, some things stay the same. You figure out where your success is, where you have margin for error, and then just trust it. You know, don’t think too much about it, just go execute.”

The uncluttered mind can be a beautiful thing this time of year, and the Dodgers have benefitted from the zen-like serenity Treinen has displayed on the mound since good health and confidence coalesced for him in late August, producing a string of scoreless outings that has stretched into October.

Treinen gave up one run and three hits in one inning of an 8-4 win over the Seattle Mariners on Aug. 21, pushing his earned-run average to 2.87 in 35 games. He has not been scored upon since, closing the regular season with 15 games in which he gave up six hits, struck out 18 and walked two over 15⅓ innings to finish with a 7-3 record and 1.93 ERA.

Treinen then threw 3⅔ scoreless innings over three games in the division series win over the San Diego Padres, including a 39-pitch, five-out save in Game 1 and a 1-2-3 ninth inning in Friday night’s 2-0 series-clinching Game 5 victory, after which his teammates mobbed him on the mound.

“It’s huge,” manager Dave Roberts said, when asked how Treinen’s dominance has changed the dynamics of his bullpen. “There was a point in the middle of the year where he was kind of scuffling a little bit, but he’s pitched in some huge games. To have him back to being dominant has certainly made everyone else around him better.

“To be able to deploy him at any point in time to go multiple innings, versus right and left, all of that stuff has stabilized us. He’s got a crazy-good look in his eye as far as being possessed. Honestly, I think 26 guys in that room feel that way, have that same look. But the guys in the bullpen, they’re all kind of in that good spot.”

The bullpen might be the primary reason the Dodgers overcame a 2-1 deficit against the Padres, accounting for 16 innings of the 24-inning scoreless streak Dodgers pitchers closed the series with, including all nine of an 8-0 victory in Game 4. The Padres hit .136 (11 for 81) in those 24 innings.

“If you’re talking about a series MVP,” Roberts said, “it’s our bullpen, clearly.”

It took several months for Treinen, who missed most of the 2022 season because of a shoulder injury and all of 2023 after undergoing surgery to repair rotator-cuff and labrum tears, to regain the form that made him a key contributor to the Dodgers’ 2020 World Series-winning team and one of baseball’s best setup men in 2021.

“A lot of it is God’s grace on the way my body’s been doing,” Treinen said. “I’ve been fine all year, but post-surgery, there’s just aches and rustiness that I had to work through.

Dodgers reliever Blake Treinen delivers a pitch against the Giants during a game in July at Dodger Stadium.

(Gina Ferazzi / Los Angeles Times)

“You have to regain the integrity of the shoulder throughout the season, but the last month or so has been as close to normal as it’s ever felt. I can just see glove, hit glove, trust body as opposed to getting to a spot and throwing. So it’s just overall health.”

Treinen looked so good early in spring training that the Dodgers thought he might recapture his 2021 form, when he went 6-5 with a 1.99 ERA in 72 games, striking out 85 and walking 25 in 72⅓ innings while holding hitters to a .179 average and a .512 on-base-plus-slugging percentage.

Then a Cactus League comebacker drilled Treinen in the right rib cage March 9. Initial medical scans showed an internal bruise with bleeding in his lung. Doctors subsequently diagnosed a pair of rib fractures that sidelined him until early May.

Treinen opened his season with 14 scoreless appearances before walking three batters and giving up a grand slam to Kansas City’s MJ Melendez in a 7-2 loss on June 15. He hit another rough patch in late July, giving up a walk-off home run to Alex Bregman in a 7-6 loss at Houston on July 27 and solo homers to Manny Machado and Jackson Merrill in the ninth inning of a 6-5 loss at San Diego on July 30. He has been virtually untouchable since then.

What makes Treinen so difficult to hit is the movement he gets on his two primary pitches, an 84-mph sweeper that, according to Baseball Savant, drops an average of 40.7 inches with a 15.2-inch glove-side break, and a 94.6-mph sinker that drops an average of 27.2 inches with a 16.5-inch arm-side break.

The velocity of Treinen’s sweeper is down from his 86.4-mph average in 2021, but he’s getting more action on it, the pitch averaging 37 inches of drop and 13 inches of break in 2021. Treinen held opponents to a .120 average (nine for 75) with 37 strikeouts in at-bats ending with the pitch this season.

Since Treinen’s success often is predicated on getting ahead of batters and getting them to chase his sweeper out of the zone, his 65.8% first-pitch-strike rate, which was considerably better than his career average of 60.9%, has played a huge role.

Treinen also throws a 90.8-mph cut fastball that has a much tighter break than his sweeper and a 94.3-mph four-seamer that is less lively than than his sinker — it breaks an average of eight inches to his arm side — but is easier to command.

“Knowing when to be in the zone and when to be out of the zone is the biggest thing,” Treinen said. “Some guys cover lateral well, some guys cover vertical well. For guys who cover vertical, I can play my lateral game in the zone and be OK. For guys who cover lateral, I can play the up-and-down game.

“It’s understanding how to set up your next pitch and, potentially, two or three pitches away. It’s all predicated on being ahead. Batting averages are a lot better on 1-0 and 2-0 counts than they are on 0-1 and 0-2 counts.”

Treinen’s dominance, coupled with the trade-deadline acquisition of hard-throwing right-hander Michael Kopech and Evan Phillips’ return to form after a brutal July (11.74 ERA in 10 games), has armed Roberts with the kind of three-headed relief monster the Royals had when they rode Greg Holland, Wade Davis and Kelvin Herrera to a World Series title in 2015.

Twice in the final week of the regular season, Roberts used Treinen against the heart of the Padres order — Fernando Tatis Jr., Jurickson Profar and Machado — in the eighth inning of a 4-3 win on Sept. 25 and an NL West-clinching 7-2 win on Sept. 26.

Roberts extended Treinen in the NLDS opener — only twice this season did Treinen throw more than an inning in a game — and Treinen responded by striking out Donovan Solano with an 84-mph sweeper with the bases loaded to end the eighth inning and Machado with an 85-mph sweeper with two on to end the ninth.

Blake Treinen celebrates after earning a save in Game 1 of the National League Division Series against the Padres.

(Robert Gauthier / Los Angeles Times)

The more stressful the situation for Treinen, the deeper the Dodgers play into October, the slower his heart seems to beat. Amid all the pressure-packed moments of the playoffs, Treinen traveled to Washington on Thursday’s off day for the birth of his third child, a daughter named Quinn, and was back at Dodger Stadium to close Friday night’s game.

“I’m glad it’s intense for the everyday baseball fan and I’m glad it’s intense for other players, but I just have a different perspective, and I’m not sure why,” Treinen said. “For me, the moment can’t be bigger than whatever it is. If you focus on doing your job and executing, why stress about it?

“Of course, I want to win and reach the World Series. But you don’t need to add stress or expectations to the situation. Just do what you know you’re capable of doing, what I’ve been doing for 30 years of my life, and that’s throwing a baseball.”