MLB's hardest-throwing pitcher Mason Miller is menacing hitters: 'Scary to see, fun to watch'

BALTIMORE — Baseball has made Mason Miller famous, and one day it might make him very wealthy, but most of all, his journey through the game has taught him impermanence – be it within the white lines or outside them.

When Miller was a 20-year-old collegian struggling to keep weight on his 6-5 frame and add velocity to a fading fastball, he learned type 1 diabetes would be his reality the rest of his life.

After Miller ironed out his health issues, was drafted in 2021 and then summoned by the Oakland Athletics to the big leagues in 2023, an encouraging run as a starter was cut short by an elbow injury – and life in the bullpen was his reality.

And as Miller began locking down the ninth inning, ensuring his spot in the big leagues and becoming a favorite among beleaguered A’s fans, he and teammates found out they will call a minor-league park home for the following three seasons.

Yet Miller has come through it all with the most dominant fastball in the major leagues, sending Statcast haywire and emerging as the must-see element of an A’s team that may be functionally homeless but is suddenly easier on the eyes.

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His starter path and reliever outcome has created a monster.

“I feel like Mason’s different than a lot of closers,” says A’s starting pitcher Paul Blackburn. “A lot of guys just throw hard and sometimes will run into command issues. Mason has starter command with closer stuff.

“And that’s scary to see. And fun to watch.”

Now a firm 200 pounds, Miller has unleashed the hardest fastball in the major leagues this season, topping out at 103.7 mph. He owns eight of the nine fastest pitches this year, and his 86 pitches of at least 100 mph are nearly double that of Michael Kopech, who’s No. 2 on the list.

It is his slider that’s perhaps the ultimate separator, earning a 47.1% whiff percentage, and such is the luxury of a closer with multiple plus pitches.

Beyond the gaudy gun readings, Miller has allowed just 11 baserunners in 12 ⅓ innings, with a 25:4 strikeout-walk ratio. His trial by fire came this past week, when he was tasked with protecting a 2-0 lead at Yankee Stadium, with Anthony Volpe, Juan Soto and Aaron Judge due in the ninth before a crowd of 40,141.

Fourteen pitches later, all had struck out, on pitches ranging from 102.5 mph to 103.3 mph.

“You can’t not feel that kind of adrenaline,” says Miller, who has saved seven games, yet exudes a mentality like he’d worked ninth innings for years. “You feel that atmosphere, the fans, the moment in the game, the situation – it all adds up, for sure.

“Being able to pour it all into one at-bat – I’m not saving anything, I’m not hiding anything. It’s going to be my best from the moment you step in the box. And obviously they’re bringing their best effort, too.

“That moment, it just feels like all that competitive juice just gets compressed into that one at-bat, that one inning.”

It’s all certainly a rush to the head for Miller, a starter until a UCL sprain sent him to the injured list for four months of the 2023 season. There are reminders, here and there, of how delicate this professional life is, both on an individual and team basis.

“I enjoy any opportunity I get,” he says, “to be on a big league mound.”

Lights out

Miller’s just wrapping up his first month as a big league closer, and not all the trappings of the gig are totally in place. Oh, the Oakland Coliseum blares his entrance song, Nickelback’s "Burn It To The Ground," when he jogs in, and his wife reports that the accompanying video is pretty cool.

The light show that heralds so many closers’ entrances around the majors might need to wait a year or four, though.

“The lights at the Coliseum probably aren’t suitable to go off,” Miller notes in his understated baritone.

“It might take a couple minutes for them to come back on.”

Indeed, the decaying Coliseum’s lights sometimes don’t come on when they want, although at least the facility offers three decks of seating and a big league clubhouse. From 2025-27, the A’s will strip Oakland from their name and decamp to Sacramento, while waiting for final hurdles to be cleared and construction to presumably unfold on a new stadium in Las Vegas for 2028.

For a club with either young talent years from arbitration – like Miller, who says peeking at Las Vegas real estate would be foolhardy so early in his career – or players on one-year deals, such uncertainty and indignities have been part of the gig for the past three years.

“The only day that matters right now is today,” says Miller. “All that stuff is out of our hands. And all we can do is go out and play ball. Whether that’s in Sacramento next year, whether that’s with another team – any number of guys, nothing’s really guaranteed, unless you’re on a guaranteed deal, with a no-trade clause.”

Exactly zero A’s are guaranteed a 2025 contract. Yet a club that lost a franchise-worst 112 games last season is holding its ground this year.

The A’s are 12-17 after splitting four games at Yankee Stadium – Miller closed out the last one, too – and winning two of three at AL East champion Baltimore.

“We kind of started off so bad last year that nobody noticed how we played from the All-Star break on,” says Blackburn, a 2022 All-Star who has a 3.34 ERA in six starts.

Oakland was 12-46 when the calendar turned to June in 2023.

“It’s kind of led into this year,” he says. “I feel like we’re a different team this year than we were the last two years.”

Particularly in the ninth inning.

At peace with the process

Miller was in his third year at Division III Waynesburg (Pennsylvania) University when a drug test was flagged for abnormalities; it eventually led to his type 1 diabetes diagnosis.

It was a startling moment for himself and his parents, who came from their home south of Pittsburgh when he was diagnosed. Yet it was a relief: Miller’s fastball velocity, he says, “was kind of going down the slide,” this at a time he should have been getting stronger.

But getting his diet and his insulin levels in check coincided with the natural growth and strength gain a 20-year-old might come to expect.

“I’m a competitor, through and through,” he says. “I wasn’t seeing success on the field. Getting everything figured out and starting to see results – all that hard work and habits and routines I’d already been doing, seeing it pay off was wind at your back, gave you that gust of encouragement to keep going.”

The kid with an ERA north of 7 his first two seasons saw it trimmed to 1.86. He struck out 97 batters in 67 ⅔ innings in 2019. The COVID-19 pandemic granted him another year of eligibility on the back end, and he transferred to Division I Gardner-Webb.

Suddenly, his fastball was crackling in the 90s. But he didn’t offer pro clubs a particularly large sample with which to work.

The A’s nonetheless grabbed him in the third round, the 97^th pick overall, in the 2021 draft.

“There were a lot of teams that had the opportunity to draft Mason Miller,” says A’s manager Mark Kotsay. “They stayed away from him, didn’t believe in him. So, let’s give credit to our scouting department and general manager for identifying this young man and bringing him here.”

Miller and the A’s dodged a bullet of sorts when his 2023 forearm strain – and ultimate UCL sprain – calmed down simply with rest, keeping him off the scroll of elite arms that have succumbed to Tommy John elbow reconstruction surgery the past two years.

While many of those shelved arms are also among the game’s hardest throwers, Miller says he’s able to block the pitfalls of pitching out.

“If you are able to be at peace with your process and what you’re doing,” he says, “that’s all you can do.”

Meanwhile, Kotsay and general manager David Forst are taking great pains to keep him on the mound. After his four-month injury absence last year, Miller was given the go-ahead to return – but only pitching a maximum of three innings, every fifth day.

He struck out 16 in 12 innings, and those six appearances gave both team and player inspiration for the coming year. Kotsay and Forst came to the conclusion: High-leverage reliever. Closer, if he can handle it.

Miller put a vise grip on the job.

“In spring training, he bought In,” says Kotsay. “He’s got some passion and some fire and all those characteristics for me align with someone who can handle those moments.”

The care continues. Miller pitched back-to-back days for the first time Thursday in New York and Friday in Baltimore. He was given two days’ rest after that stretch, the club opting for Lucas Erceg to close out their 7-6 win Sunday.

Perhaps he’ll start again one day; Kotsay wouldn’t dare glance down the road that far. Yet regardless of role or career arc, Miller has proven he’s a force.

“The stuff’s unbelievable. That’s what everyone sees,” says Blackburn. “But no one sees the type of person and makeup that he has. He’s a guy that always wants the ball on the back end, and no one’s going to beat him.

“That’s really our goal – to get the ball in his hand.”