You’d be forgiven for thinking that the hottest thing in baseball is Archie Bradley’s face.

The 6-foot-4 right-hander, after pitching his first two seasons with at most a few days of growth on his face, showed up to spring training with a beard. Over the past six months it’s grown from the kind of facial hair you need if people are going to take your bluegrass cover band seriously into a gigantic forsythia bush. Bradley’s beard is now roughly the size, shape, and color as the Pyramid of Cheops, reaching down from his jaw nearly to his collar in an exquisitely groomed trapezoid—a shape Bradley says he trusts one barber, and one barber only, to maintain.

But even though he works in a city where highs of 110 degrees aren’t uncommon, with his face covered in about a cubic foot of hair, Bradley’s perfectly comfortable in Chase Field.

“We’ve got a roof, man. It’s nice and cool in there,” he said.

Air conditioning or no air conditioning, the hottest thing in baseball isn’t Bradley’s face but his arm. The Diamondbacks reliever, two weeks past his 25th birthday, leads all MLB relievers (minimum 25 appearances) in both ERA+ (367) and bWAR (3.2). Bradley's allowed only eight runs in the 56 innings he’s pitched this season—for comparison, Boston’s Craig Kimbrel, in the midst of his best season in five years, has allowed eight runs in 53 innings.

Arizona (69-57, 3.5 games up in the NL wild-card race) is poised to make the playoffs for the first time since 2011, and despite a hitter-friendly ballpark and Paul Goldschmidt’s name at the top of the marquee, the strength of this team is its pitching staff, which currently sits third in MLB with a collective 126 ERA+. In large part, that’s the result of having five starting pitchers with an ERA+ of 110 or better in 110 innings or more, but Bradley is doing his part as the team’s shutdown reliever, even if that wasn’t where he expected to end up.

The 2011 draft was not only a great draft for pitching prospects, it was a great draft for unusual pitching prospects. Gerrit Cole had triple-digit heat, Trevor Bauer was a headstrong athletic freak, José Fernández had an eye-popping curve and off-the-charts makeup, and Bradley’s instate high school rival Dylan Bundy was an undersized high schooler with stuff you’d expect from a pitcher five inches taller and polish you’d expect from a pitcher five years older.

Unlike his peers, Bradley was an entirely conventional pitching prospect: a tall, lean right-hander from Broken Arrow High School in Oklahoma, with a big fastball and a curveball that Baseball America, which ranked him as the no. 9 prospect in the class, described as a “hammer.” It’s from this basic cloth that Noah Syndergaard was cut, as was, if you put the cloth in a mirror, Clayton Kershaw. The Diamondbacks picked Bradley seventh overall and bought him out of a commitment to play quarterback at Oklahoma for $5 million.

Over the next five years, Bradley struggled to stay healthy and keep his velocity up while his classmates sped past him. Bauer and Bundy were in the majors by the end of 2012. Fernández finished third in Cy Young voting in 2013, while Cole and Sonny Gray, who went 18th overall out of Vanderbilt, finished top five in Cy Young voting in 2015. Last year, the third Oklahoma high school pitcher taken in the first round in 2011, Michael Fulmer, was the American League Rookie of the Year.

Bradley debuted in April 2015, but struggled in his first two big league seasons—among 181 starters with at least 100 innings pitched in 2015 and 2016, Bradley posted the fourth-highest walk rate (11.1) and the 18th-highest ERA (5.18). In just his fourth big league start, Bradley took a Carlos González line drive off his face, which fractured his right sinus cavity. He returned in two weeks, only to land back on the DL in June with shoulder tendinitis that cost him the rest of the 2015 season. Suffering those setbacks so early in his MLB career only steeled Bradley’s resolve.

“Whenever you’ve had a taste of the big leagues and seen what it’s like, you don’t want to play anywhere else,” Bradley said. “After getting hurt, getting hit in the face, struggling, you just realize that you have one chance to do this and you want to do it the right way. At least for me I want to put all my eggs in this basket and cut off all the distractions and be the guy I used to be.”

Bradley arrived in spring training this year hoping to land a rotation spot and bounce back from a rough 2016 season, when he posted a 5.02 ERA over 26 big-league starts. But so did Zack Greinke, Zack Godley, Shelby Miller, Taijuan Walker, Robbie Ray, Patrick Corbin, and Braden Shipley. Come April, Bradley found himself on the outside looking in.

“They told me about a week before spring training was over that I was going to make the team and I was going to work out of the bullpen and be the long guy,” Bradley said. “That means, up big, down big—whenever they need a guy to fill some innings. I didn’t want to be in Triple-A, so I was pumped. I thought this team had a chance to be where we are right now, so I was excited to have that opportunity.”

It took only one appearance for him to show how good he can be out of the bullpen. On April 4, he took the ball from Randall Delgado in the fifth inning of an 8-2 game against the Giants. Over 3.1 innings scoreless innings, Bradley struck out seven batters. A year after Andrew Miller brought the multi-inning reliever back into style, Bradley recorded at least four outs in his first six career relief appearances, and ended the month of April with four holds, a win, a 1.13 ERA, and a .224 opponent OBP in 16 innings pitched.

“I threw in some close games early, then Shelby went down and I had a chance to go back in the rotation but they told me they wanted to leave me in the pen,” Bradley said. “They felt like what I was doing down there was better for the team, and with the way they communicated it and the way I started to figure it out, I was like, ‘All right, let’s just dive into it.’ And here we are.”

After realizing he was capable of being more than a mop-up guy, Arizona moved Bradley into a more traditional setup role. Even though he’s capable of pitching two or three innings at a time, the Diamondbacks haven’t called on Bradley to do so often since he became a high-leverage reliever. Since the break, he’s pitched 14 times, and while he’s gotten more than three outs four times, none of his appearances have been longer than five outs. Bradley hasn’t pitched more than two innings at a time since April 26.

Perhaps that will change in the playoffs or if the wild-card race tightens up. Miller’s October 2016 workload wouldn’t be sustainable for six months, but for a couple of weeks when the games get more important and there’s nothing left to save a pitcher’s energy for, it’s doable. Either way, Bradley’s learned how to handle himself no matter what shape his outing takes.

“You learn to pitch to the situation you’re pitching in,” Bradley said. “A lot of these teams haven’t seen me out of the pen, or even if they have seen me—obviously my velo’s up, that’s a big difference, but even my mechanics are a little different. I’ve got a high leg kick, high arm, ball’s coming out at different angles.”

Pitching out of the bullpen hides a bad starter’s weaknesses in one of four ways: He can throw harder in shorter spurts; he can pare down his repertoire to his best two pitches if he doesn’t have to face batters multiple times; he can throw fewer innings and stay healthier; and he can avoid matchups that might expose platoon-split issues.

Despite his shoulder issues in 2015, Bradley was healthy in 2016—he made 33 starts and threw 182.1 innings between Triple-A and the majors. And while he’s more or less scrapped his changeup since moving to the pen, he threw it only 7 percent of the time last year, anyway. In 2016, major league left-handed hitters hit .318/.412/.523 off Bradley, but this year he’s been just as tough on lefties (.209/.287/.253 in 102 PA) as righties (.188/.216/.321 in 116 PA).

The biggest change, though, has been the velocity spike. As a starter, Bradley’s fastball sat around 93 miles per hour and maxed out at 97. This year, pitching out of the bullpen, Bradley works around 96.5, and in three different games he has cranked the heater all the way up to 99 miles per hour. Bradley’s average fastball is exactly a mile per hour faster than the fastest of the 464 four-seamers he threw out of the rotation in 2015.

Some relievers are relievers out of obligation, while others get excited about coming in to stomp out a rally or close out a game. Bradley started out as the first, but as the season’s worn on he’s enjoyed the bullpen more and more.

“When you feel like you can come into a game ... and shut down an inning or shut down a rally, and you have the power to do that, it’s fun,” Bradley said.

One thing Bradley’s prioritized since his move to the bullpen is a distaste for allowing inherited runners to score. As he put it, “Nobody wants to give up somebody else’s runs.”

That statistic meshes well with words like “trust” and “protect,” which he uses frequently when talking about his fellow pitchers, and it cultivates a camaraderie he seems to enjoy. Sure enough, even though the Diamondbacks’ relievers are sixth in the NL in K%, fifth in WPA, and tied for second in ERA-, they’re tied with the Dodgers for the league lead in stranding inherited runners. Only 24 percent of Arizona’s inherited runners have scored this year, and only 19 percent of Bradley’s.

While Bradley seems happy in the pen for now—and he praised manager Torey Lovullo for being up-front about his role and expectations, both for the season and on a game-to-game basis—it seems like that happiness is partially the result of winning generating good chemistry and partially the result of Bradley having the kind of personality that leads to him being up for anything. The truth is, he wants to start again someday.

“I don’t think my starting days are over, but at the same time when you’re on a team that’s winning, and you’re part of that every day, and you’re contributing, I’m not going to question or ask why,” Bradley said. “I’m just going to keep doing what I’m doing.”

If and when Bradley gets that chance depends on a rotation spot opening up—Arizona’s top five starting pitchers are all slated to return next year, and with the exception of Corbin, they’re all locked up through at least 2020. Not only that, but Bradley's a three-win player as a reliever, and he'd have to be quite good as a starter to produce more value to the Diamondbacks in that role. However, starting pitchers tend to make more money than relievers—particularly non-closers—in arbitration, which will become an issue once Bradley hits arbitration after the 2018 season. In other words, “value” doesn’t always translate to salary.

A return to the rotation also depends on how much of Bradley’s bullpen success would translate. The velocity spike likely wouldn't, but Bradley’s also recommitted himself to working within the strike zone, cutting his walk rate almost in half since 2016, and that plays no matter how many pitches you’re throwing.

“The biggest thing is I’m just being aggressive—I’m trying to get ahead of guys and not walk guys,” Bradley said. “That’s the one thing I’ve learned—starting, bullpen, whatever—you can’t put guys on base for free. You’ve got to make them earn it.”

In a realistic worst-case scenario, Bradley is the heir-presumptive to 40-year-old free-agent-to-be Fernando Rodney as the team’s closer, and he’s still only 25. And while being a big league closer isn’t starting, it beats the heck out of Triple-A.

All stats current through Monday’s games.