How a diabetes diagnosis turned around A’s closer Mason Miller’s career

Mason Miller is a big leaguer because of a failed drug test.

This was back when Miller played Division III ball at Waynesburg University, a school 50 miles south of Pittsburgh and a million miles from the majors. Miller was a local kid with a decent arm but a 7.00 ERA in two college seasons. He landed a finance internship at a local hospital following his sophomore year, but his required drug screen was flagged as diluted. When Miller objected, the lab coordinator ran another test and told Miller there were two possibilities in play, and “neither is good.” Either Miller had diluted the sample in an attempt to manipulate the outcome of the test or he had dangerously high blood sugar.

Miller was admitted that day to UPMC Children’s Hospital of Pittsburgh. He was diagnosed with Type 1 diabetes. It answered a question Miller had been asking a lot: What’s wrong with me? He was exhausted. He’d dropped from 180 pounds to 155. He had lost stamina and some of the sizzle on his fastball.

He’d never have guessed that diagnosis would change the course of his career.

In the Oakland A’s clubhouse one day this spring, Miller lifted his T-shirt to show a glucose monitor taped to his abdomen. He changes the monitor every 10 days, checks his blood sugar levels on his phone, and uses an insulin pen when he eats and before he goes to sleep. It was scary learning about how to manage diabetes while at the Children’s Hospital six years ago, he said, but it was also remarkable how quickly his body changed afterward.

Miller has gained weight, muscle and velocity every year since. The 25-year-old A’s closer now stands 6-foot-5 and 220 pounds. The kid whose fastball topped out at 88 mph in high school and still sat below 90 mph before the diagnosis now has the highest average fastball velocity in the majors this season: 100.6 mph. “Mass is gas,” Miller said with a laugh, last month after throwing his hardest pitch to date, almost 104 mph. (He clarified: “103.6. Can’t round up past 100. That’s the rule.”) He added a tenth last week, hitting 103.7 mph.

Mason Miller threw the four fastest pitches in the Majors this season en route to a save for the @Athletics 🔥

The rookie dialed it up as high as 103.7 mph and hit 101+ on all nine of his heaters: pic.twitter.com/ltipOL7zGl

— MLB Pipeline (@MLBPipeline) April 11, 2024

On Wednesday, he fired a 102.7 mph fastball past the St. Louis Cardinals’ Brendan Donovan to secure his fourth save in four tries. Miller allowed two runs in his first outing this season, but eight scoreless innings since then have lowered his ERA to 2.00. He has struck out 16 of the last 30 batters he has faced, and he’s gotten more of those on his best pitch — a slider — than with a triple-digit heater.

“It’s electric stuff,” A’s outfielder Brent Rooker said. “It’s overpowering.”

Mason Miller, Obliterating the Side.

The most electric pitcher in baseball. ⚡️⚡️ pic.twitter.com/yGmOxjAYje

— Rob Friedman (@PitchingNinja) April 14, 2024

Before the diagnosis, it wasn’t even Division III overpowering.

Miller hadn’t gone to Waynesburg with the majors in mind. He was a cyber-school student, playing baseball and golf at the local high school and taking extra classes at a community college. He wanted to be the first in his immediate family to get a college degree. A couple of Division I coaches told Miller he could try out for their teams, and he had an offer to pitch at Division II Gannon University, but Miller chose to stay closer to home and attend Waynesburg on a community service scholarship. “I was never a can’t-miss guy,” he said. He always figured his future featured finance, not fastballs.

Waynesburg head coach Perry Cunningham, the team’s pitching coach at the time, recalled Miller arriving on campus as a towering, thin 18-year-old with puzzlingly poor stamina. He’d tire in the third or fourth inning, losing both location and sharpness on his pitches. Miller had a 7.03 ERA as a freshman. He returned as a sophomore, on a mission to pitch deeper into games, and posted a 7.16 ERA. The coaches kept riding Miller to put on weight, but he swore he was eating right and hitting the weight room hard.

Then came the diagnosis. They stopped riding him.

There’s now a long line of major leaguers who have successfully managed Type 1 diabetes — from Jordan Hicks to Adam Duvall to Sam Fuld to Jason Johnson to Garrett Mitchell, among others — but Miller knew nothing about that group at the time. No one in his family is diabetic. From his first pitch his junior year, Miller said, “I dominated.” He had a 1.86 ERA, striking out 97 in 67 2/3 innings. Cunningham reached out to a few scouts he knew. After Miller had a workout for the hometown Pirates, his mother had questions.

“I remember her being in somewhat disbelief: ‘Is this real? Are they messing with my son?’” Cunningham said. “I was like, ‘No. If you start throwing this hard, with this height and this frame, there’s going to be real interest.’”

Still, it wasn’t until after the COVID-19 pandemic shortened his senior season that Miller fully focused on playing pro ball. As he wrapped up his final courses from home, he learned he’d receive a fifth year of NCAA eligibility. Miller saw it as a win-win. He could get an MBA and chase his baseball dream for one more year. Miller met with Waynesburg’s then-head coach Mike Humiston and Cunningham, who encouraged Miller to transfer: “There’s no reason for you to come back here. It is, quite frankly, not in your best interest. There’s nothing left to prove.”

Miller transferred to Division I Gardner-Webb, where pitching in front of scouts each start he went 8-1 with a 3.30 ERA and struck out 121 in 92 2/3 innings. It was Miller’s first year away from home, and it may have set up his career for a quicker ascent through the minors. “Different team, different round, different priority,” Miller said. “I think it all happened for a specific reason.”

Then again, Miller might have made it anyway. He saw 100 mph on the radar gun for the first time in his rookie-ball debut.

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A's prospect Mason Miller riding a 100-mph fastball into the AFL spotlight

The A’s third-round pick in 2021, Miller shot up to Triple A in 2022 and pitched in the Arizona Fall League. The Athletic’s Keith Law listed him as Oakland’s No. 5 prospect last spring and said he’d be a top-100 prospect were it not for the health concerns: “If he holds up, he could be a No. 2 (starter) or better — and to be clear, I’m hoping he holds up. It’s just that the odds are against it.” Miller, who has a screw in his right elbow from a youth baseball injury, missed some of the 2022 season with a scapula strain.

Miller was called up last April after throwing just 45 1/3 innings in pro ball. A’s manager Mark Kotsay wasn’t just familiar with his stuff; he’d been bugging GM David Forst to bring Miller to Oakland. “I asked for him a year before he came up,” Kotsay said. “Those arms generally play.”

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What to expect from the A's Mason Miller in his MLB debut

Miller debuted on a Wednesday afternoon at Oakland Coliseum. The A’s were 3-15 before losing by 10 runs to the Chicago Cubs that day. But the kid touching 102 mph in the second inning had everyone’s attention. In the stands were his now-wife, Jordan, his parents, Matthew and Kirstin, his younger siblings, Zach and Corinne, and a few friends who’d traveled across the country from Bethel Park, Pa. Miller met Jordan at Waynesburg. The couple still calls Western Pennsylvania home. In their Canonsburg, Pa., rental are a few authenticated baseballs and the framed lineup card from Miller’s debut.

102 mph to strike out the side 🔥 pic.twitter.com/hpYMSmfVuD

— A's on NBCS (@NBCSAthletics) April 19, 2023

In his third career start, Miller threw seven no-hit innings against the Seattle Mariners.

But then came another injury — a mild UCL sprain. He missed four months. “That sucked,” Miller said. “But I avoided anything major, which is good. I tried to find the silver lining in it.” When Miller returned in September, the A’s moved him into a multi-inning relief role. Given Miller’s injury history and how diabetes could impact his recovery time, Kotsay said, it made sense to lighten the workload further by bringing Miller out of the bullpen in 2024. Miller bought into that plan, and is acing the test, but is still leaving the door open to getting stretched out as a starter down the road.

So far, velocity on both his fastball and slider — he’s effectively ditched his cutter and changeup in the relief role — are up two ticks year over year, and he hasn’t lost movement as he lets it eat.

“The only thing I’m looking for from Mason is that he stays healthy,” Kotsay said. “He’s got all the ability. He’s got the arsenal to be a closer. Now it’s just keeping him healthy and allowing him to go out and perform.”

A’s first baseman Ryan Noda faced Miller in live batting practice while the two were both rehabbing injuries last summer. The battles, Noda said, were a blast. “Mason is a bulldog on the mound. No matter what role he has, he’s going to come out and give his all. Sometimes he’ll hit 104.”

Or 103.7. Can’t round up past 100.

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(Photo: Thearon W. Henderson / Getty Images)