They make for an atypical pairing, born 25 years apart, each with his own quirks. But midway through their first season as a tandem, they seem inseparable.

“I’ve enjoyed learning from him,” said Doolittle, who noted invaluable lessons about the craft of pitching as well as the way the veteran coach teaches and interacts with players. “He’s got a really impressive track record and a long time in this game of doing this.”

Hickey has been the Washington Nationals’ pitching coach since the 2021 season. Doolittle retired from an 11-year major league career in relief last September, then took a job as pitching strategist (a gussied-up phrase for assistant pitching coach) in January. Together, they have shepherded MacKenzie Gore, Jake Irvin, Mitchell Parker and Trevor Williams to breakout seasons and guided a deep bullpen, a revelation that has kept Washington, against all projections, in the postseason hunt.

Entering Monday, the pitching staff has improved its ERA from 5.02 to 3.86, a bigger jump than any team other than the Kansas City Royals. The Nationals have cut their walk rate by more than any team except the Oakland Athletics. They went from conceding the most home runs in the majors to the fourth fewest. They did so without adding any starters in free agency and with their lone 2023 all-star, righty Josiah Gray, on the injured list since early April. It’s the same cast as last year, save for a few middle-inning relievers and two previously unheralded left-handed rookies.

“Well, you get the mix,” closer Kyle Finnegan said. “You know, Hickey has been around forever. He’s worked with some legendary pitching staffs. So he’s got like this — I wouldn’t call it old school; he’s very analytical and he knows everything. But he can kind of filter it down to a way that’s clear and concise and it comes out in simple terms, but you know that there’s lots of thought behind it. And then Doolittle is great with the video and the metrics and the TrackMan data. Doolittle played with some of us, so he knows what we do when we’re going well. And he’s still like a player, so he has that verbiage just like you’re talking to your buddy. So it’s like they’re yin and yang.”

Last year, the Nationals went the entire season without an assistant pitching coach. General Manager Mike Rizzo wanted to remedy that. In the offseason, the team laid out a framework: Doolittle, using his background as a player and aptitude with analytics, would assist Hickey in interpreting and presenting information to players.

These days, it would be hard to imagine a world without them together, trolling through information or popping around to different players with thoughts on a pitch grip. When pitchers are asked about a mechanical tweak, a game plan or an overarching philosophy, rarely do you hear one coach’s name without the other’s.

As the pair sits down for an interview, they chuckle when asked whether Hickey’s job is any easier now.

“I don’t know if I would use the word ‘easier,’” Hickey said. His responsibilities and workload haven’t changed. “But I absolutely, positively feel like there’s a lot more support. Nothing is going to go unnoticed, or nothing’s going to fall through the cracks.”

That is, perhaps, the simplest place to start.

Doolittle and Hickey explain it like this: Every player learns differently. There’s also, conveniently, multiple ways to teach most things. Some pitchers like to see cold, hard numbers. Others like things explained by feel. That’s why there are two of them.

In spring training, Doolittle began by trying to relay an objective piece of data — one or two numbers per pitcher — that explained why each was unique and why it made him effective. For Irvin, for instance, it was his extension, the approach angle on his four-seamer and the horizontal break on his breaking ball. Or with Parker, it was the induced vertical break on his fastball coupled with his approach angle.

“And so we start to say, ‘This isn’t just us hyping you up,’” Doolittle said. “‘This is what makes you effective. This is why you should have confidence to attack the zone and throw strikes because there’s not a lot of guys that are giving the hitters these kinds of looks.’”

In one interview after another, pitchers attested that they felt more prepared and less predictable this season. Reports before starts and between innings, they said, have been more detailed. Frequently, Finnegan said, he has been able to remember their cues when he finds himself in a tough spot. “All of a sudden,” he said, “you just feel another burst of confidence, and you feel like you got a chance to get them out.”

The examples seem endless. Finnegan didn’t grasp how much better his fastball played up in the zone — and why — until Doolittle worked him through the data this past offseason. Doolittle sat with lefty reliever Robert Garcia and explained that his slider was a huge swing-and-miss pitch when it had negative vertical break and wasn’t that when it had positive vertical break. Irvin’s backup cutter went from an afterthought to an asset once Doolittle tweaked his release. This month, he repaired Jacob Barnes’s rotation toward the plate, which helped the right-handed reliever out of a command-related funk.

“That is awesome to hear as a player, that you know a coach is going above and beyond,” Garcia said when asked about Doolittle. “On off days, he’s watching eight hours of video. He does not stop working. You ask him questions, and he knows the answer to them. He finds it right away.”

As for Hickey: A multitude of pitchers described the coach’s knowledge of opposing hitters, his ability to read mechanics and body language, as uncanny. In mound visits, Hickey has been a stabilizing force that has kept a bad pitch from spiraling into a bad outing. His superpower is simplifying, translating the thousands of data points in his mind to a message that the pitcher can execute on.

“Doolittle might like looking at video a little bit more and getting into that. Hickey might like more of the aggressive approach of first-pitch strikes or trying to get early outs,” Barnes said. “They both have things they like, and I think it blends well because they both can do both of the routes. But I think they’re like, ‘Well, he likes doing that, so we’ll let him kind of focus on that, and I’ll focus on this, and we’re both able to get the information in the right way.’”

When it comes to their success, perhaps the most concise way to explain it boils down to “throwing more strikes.” That is a credit to Hickey, who has prioritized it incessantly since the start of spring training. When you’re behind, Irvin recounted Hickey saying, it’s like facing Barry Bonds; when you’re ahead, it’s like facing the worst hitter in the majors. That stuck.

But it’s more nuanced than that. Most publicly available evaluations rank the Nationals’ stuff — the movement and velocity on their pitches — in the bottom half of MLB. Having the confidence to live in the strike zone works only if pitchers know what plays well in the zone, and for Washington’s staff, that’s a more limited selection.

This year, they know their stuff, they know how to sequence it, and they trust it. Nine times out of 10, Hickey estimated, throwing strikes is about intent rather than mechanics. Throwing strikes, they have begun to say, is contagious. There was the game in early June when Gore said the rest of the staff was trying to “go out there and be like Mitch and Jake,” who have located in the zone more than almost any starters in MLB. To see other members of the staff limit their walks — and to see it pay off — is reaffirming.

It’s in moments such as these that Hickey and Doolittle like to deflect credit, and understandably so, to the pitchers: They are the ones putting in the work and executing. But it’s a two-way street. And there are now two people on the other side of it.

“They’re both super smart guys, and they have their own style,” Finnegan said. “But when they’re together, it works well.”