Where does Twins flamethrower Jhoan Duran rank among MLB rookie relief greats?

Early this spring, after the MLB lockout ended and Twins camp was underway in Florida, starter prospect Jhoan Duran got moved to the bullpen following an injury-wrecked 2021 season in the minors. It didn’t take long before there were rumblings about the 24-year-old right-hander emerging as a possible Opening Day bullpen option. That’s what happens when you throw 103 mph.

Rocco Baldelli has a well-earned reputation for being tight-lipped about such things, often going out of his way to avoid publicly projecting future plans, but even the Twins manager found it tough to keep the Duran hype from growing. After each dominant spring outing, Baldelli was asked about Duran’s odds of making the team, and his answers became less and less guarded.

Finally on March 25, about two weeks before the rescheduled opener, Baldelli all but announced that Duran would be making the team.

“I wouldn’t close the conversation on him,” Baldelli said. “I know he’s missed some time with injuries, but he’s got a ton of ability. He handled himself very well in camp. Obviously, the stuff stands out when you’re watching him on the mound. But just the way that he took his time, made good pitches — the game didn’t really speed up on him in any way.”

Those may seem likely fairly innocuous quotes, but in Baldelli-speak that’s akin to seeing “HE’S MAKING THE TEAM” on a flashing neon sign. Duran had been exclusively a starter since the Twins acquired him from the Diamondbacks in the 2018 trade for Eduardo Escobar, and elbow problems limited him to just 16 innings last season, but his talent was simply impossible to ignore.

Five months later, Duran is one of the best relievers in baseball.

“He’s been magic,” Baldelli said. “And he doesn’t pitch like just some guy with a good arm who throws 100. He’s turning into a pitcher. You watch the way he attacks hitters and can do different things with the ball. The strike-throwing, and being able to pitch in and out of the zone. He’s progressed immensely.”

You read that right, John Duran is tossing 103. pic.twitter.com/PAQmUKdL7F

— MLB (@MLB) May 7, 2022

Initially, the plan was to work him into the bullpen mix gradually. Duran’s first five appearances were low or medium leverage. He struck out 13 of the first 29 batters he faced, throwing the fastest pitch in Twins history and then breaking his record several times. In his sixth appearance, Duran pitched the eighth and ninth innings of a tie game against the White Sox. He hasn’t looked back.

Since that first high-leverage opportunity April 24, he has a 1.54 ERA and 57 strikeouts versus just 10 walks in 47 innings. During that four-month span, Duran is second among American League relievers in Win Probability Added, which measures a player’s impact on wins and losses. He also ranks among the top 10 in ERA, strikeout rate, strikeout-to-walk ratio and ground-ball rate.

Despite the early low-leverage work, and rarely being deployed in a traditional closer role, Duran has faced the league’s sixth-most high-leverage plate appearances, proof that the Twins have found game-saving situations to use him even if they aren’t t always save situations. And he’s thrived in those high-leverage spots, with a 1.29 ERA and .183 batting average against.

“He seems to be pretty relaxed in those types of situations,” Baldelli said of the soft-spoken, even-keeled Duran. “He’s not going to overheat, I’ll tell you that.”

Duran has almost unmatched raw stuff, as evidenced by the fact that a 103 mph fastball may not even be his best pitch. His mid-80s curveball, thrown about 30 percent of the time, has held opponents to a .127 batting average and generated a whiff on 44 percent of swings. And for many hitters gearing up for the triple-digit heat, the curveball has rendered them frozen for called strikes.

On a per-pitch basis, Duran has the best curveball in the AL, with a run value of -2.2 per 100 pitches, narrowly ahead of All-Star starters Shane McClanahan (-1.9/100) and Justin Verlander (-1.8/100 ). Meanwhile, his fastball rates “only” seventh best in the AL. What’s particularly remarkable is that he’s consistently thrown both pitches for strikes, harnessing electric stuff like a polished veteran.

“He’s not a thrower, he’s a pitcher,” Baldelli said. “He made that clear with the command, the presence and all of the stuff you need to be a good major-league reliever. We’re talking about one of the best in the world at what he does.”

John Duran, 103mph Fastball and 90mph Curveball, Overlay.

LOL. Good luck. pic.twitter.com/lYVDSgvEOY

— Rob Friedman (@PitchingNinja) June 6, 2022

There is, as Carlos Correa would say, a lot of red on his Baseball Savant page.

Duran is the hardest-throwing pitcher in baseball, averaging a majors-leading 100.6 mph on fastballs. He’s in the 90th percentile or higher in strikeout rate, swing-and-miss rate, expected batting average, expected slugging percentage and out-of-zone swing rate. And no pitcher, in either league, has thrown more innings with a lower Statcast expected ERA.

Duran has allowed multiple runs in an appearance just three times since taking on a high-leverage role in late April. After the first rough outing, he threw 13 straight scoreless innings. After the second one, he threw 11 straight scoreless innings. And since the third one, he’s allowed two runs in 16 innings. He’s rarely struggled, and when he has, it’s never snowballed.

“Duran has a good mind,” Baldelli said. “He’s very aware and pays attention. He’s not the first to speak, but he’s always listening and paying attention.”

For most of the season, the rookie’s steady excellence kept an otherwise shaky bullpen from collapsing under the weight of struggling veterans Emilio Pagán, Tyler Duffey and Joe Smith. As a whole, the Twins’ bullpen ranks 17th out of 30 teams in Win Probability Added, right around average. But if Duran’s numbers were removed, the Twins’ bullpen would plummet from 17th to 26th.

Baldelli and the Twins’ front office knew Duran was capable of making a huge impact. It’s why they handed an opening-day bullpen spot to a prospect with no previous relief experience who spent the final four months of last season on the Triple-A injured list. But even they could never have imagined him being this dominant, this soon, this consistently.

“Regardless of how much ability a guy has, there are no guarantees,” Baldelli said. “He’s followed through in every way and probably exceeded anything we could have hoped for. Everything that we’re seeing right now is more than we were banking on. You can dream all you want or believe in a guy all you want, but he has to show you. And he’s shown us a lot.”

John Duran, 103mph ⛽️

And patented K Skip pic.twitter.com/RWIZxeUOPH

— Rob Friedman (@PitchingNinja) August 6, 2022

In general, the best thing a pitcher can do is strike out a batter. Failing that, the next-best thing is to get a batter to hit a ball on the ground. Doing one of those two things well is often enough for a reliever to find success. Doing both things well is an almost guaranteed recipe for success. This year, Duran is the lone MLB reliever getting at least 30 percent strikeouts and 60 percent grounders.

How rare is that combo? No reliever with at least 200 career innings since 2010 has managed 30 percent strikeouts and even 50 percent grounders, let alone 60 percent. And only Dellin Betances and Andrew Miller — two of the era’s most dominant relievers in their primes — have topped 30 percent strikeouts and 45 percent grounders. Duran is cooking with a rare but ideal recipe.

There’s little doubt Duran is having the greatest season by a rookie reliever in modern Twins history. Going back to 1982, when the Twins moved into the Metrodome, he’s No. 1 in ERA, ERA+, strikeout rate, strikeout-to-walk ratio, OPS and WPA among their rookie relievers with at least 50 innings. To put his rookie impact in proper context requires looking beyond Twins history.

He’s having one of the best seasons by a rookie reliever, period.

Duran has racked up +3.4 Win Probability Added through the Twins’ first 120 games, which is already 14th-best among rookie relievers since 1990.

If he keeps up his current, season-long pace, Duran will finish with +4.6 WPA, which would be No. 2 among rookie relievers since 1990, behind only Jonathan Papelbon with the Red Sox in 2006. Even if Duran slows a bit, finishing with a top-five WPA for a rookie reliever since 1990 appears well within reach. His raw numbers are great, but as WPA shows, his impact is even greater.

Each time Duran breaks his record for the fastest pitch in Twins history, reporters gather at his locker to ask him about it and his reaction is the same mix of confusion and disinterest. It’s nothing new, Duran always explains, he’s been doing it for most of his life. But there’s nothing common or normal about what Duran is doing. He’s been one of the best rookie relievers of all time.

(Photo: Andy Clayton-King / Associated Press)