Of the 460,000-plus outings by a starting pitcher in Major League Baseball history, among the ugliest came a little more than a year ago. Hunter Brown, a right-hander for the Houston Astros with a high-octane fastball and an array of off-speed pitches, allowed nine runs to the Kansas City Royals and mustered only two outs. He yielded 11 hits, the most ever for a start of less than one inning.

In the weeks following the thrashing, Brown journeyed to find the version of himself who had gone from unheralded high schooler to standout at Division II Wayne State to major league rotation piece. He asked hard questions — of his teammates and himself. He weathered a few more middling outings and was on the cusp of a demotion. And he realized that in order to secure his future, he needed to look into his past and reacquaint himself with a long-abandoned pitch.

“He embraced that ass whooping,” Astros closer Josh Hader said, “and just became who he is now.”

Today, the 26-year-old Brown is one of the best pitchers in baseball. Since a transformative relief appearance last May, in which he unleashed a two-seam fastball he had stopped throwing five years earlier, Brown owns the best earned run average among American League starters at 2.20, nearly a quarter-point better than reigning AL Cy Young winner Tarik Skubal. Only Paul Skenes, arguably the game’s finest starter, has a lower ERA in that time frame than Brown. In six starts this season, Brown sports a 1.22 ERA, has struck out nearly six times as many hitters as he has walked and resembles the archetypal modern pitcher, marrying velocity with a six-pitch arsenal that consistently flummoxes hitters.

It all started May 11, 2024, in Detroit, where Brown grew up rooting for the Tigers and trying to emulate Justin Verlander. He had fiddled with seemingly everything since the Kansas City nightmare, changing his stride and hand placement during his delivery to no avail. He had sought counsel from teammates — Verlander, Hader and veteran reliever Ryan Pressly. His best advice came from hitters, though, when Brown presented them with a question: If you were facing me, what would you be looking for?

“Oh, Brown, that’s easy,” nine-time All-Star second baseman Jose Altuve told him. “Hard and away.”

Brown asked Astros shortstop Jeremy Peña the same question and was greeted with the identical answer. Ditto for longtime Astros third baseman Alex Bregman. Each said Brown’s arsenal, with his four-seamer, cutter, slider and curveball breaking to his glove side, needed a complementary offering inside to right-handed hitters particularly. His two-seamer re-debuted May 5 against the Mariners but found its footing six days later at Comerica Park.

“It’s no secret. At the time I was pitching terribly,” Brown said. “I knew I was running out of time. Something had to give. I just switched my mentality. Like, all right, this is going awful. I got to see all my family and friends, and I was like, ‘You know what, if this is my last major league game for a while, I’m gonna go out there and let it all loose.'”

Brown entered the game in the third inning determined to embrace a pitch he had ditched when the Astros chose him in the fifth round of the 2019 draft. While others, including Statcast, call it a sinker, it doesn’t have the standard boring action of the pitch. Brown says it is a “flat, running” fastball thrown with a two-seam grip — and he is convinced it helped salvage his career. He limited the Tigers to one run on five hits over five innings with seven strikeouts that day.

He picked up the pitch almost immediately because of his familiarity with it. During his three seasons at Wayne State, Brown threw almost exclusively a two-seamer and slider. When he entered the Astros organization, their philosophy was simple: Pair a hard breaking ball with a top-of-the-zone four-seam fastball and find success. He did and shot through Houston’s system after COVID, joining the Astros for the stretch run of their eventual World Series victory in 2022.

Brown’s ability to add pitches had already endeared him to Houston’s development staff. During his draft year, he filled out a survey for the Astros on his pitch mix and said he threw a curveball even though he had scrapped it in college. Early in his time with the Astros, coaches asked him to throw the curveball just to see what they had. After the first curve Brown tried, a coach chimed in: “Yeah, you’re gonna keep throwing that.”

Considering he had added a changeup and cutter during his time with the Astros, too, Brown didn’t fret about the rebirth of his two-seamer. The pitch didn’t need to move like his teammate Framber Valdez‘s. It simply served as a reminder to hitters that Brown wasn’t afraid to throw inside and that they couldn’t hunt the rest of his arsenal on the outer half of the plate.

“I wanted to go back to just athletic throwing,” Brown said. “I don’t want to be a robot. I think people get so locked in and dialed into repeating the exact same delivery every single time, which, yes, in a vacuum, if you can do that, that’s awesome. There’s not a lot of guys that can actually do that over the course of the season. I kind of just like taking — I don’t wanna say a whiffle ball-in-the-backyard approach, but realistically, that’s what you’re trying to do. It’s just against the best players in the world.”

Over time, as the two-seamer paid dividends and was further incorporated into his pitch mix, Brown regained his confidence and began to understand the advice Verlander was giving him. Mindset isn’t just important, Verlander said. It’s everything. If a hitter gets jammed and flares a ball into the outfield, that’s not bad luck worth lamenting; it’s a reminder that process trumps outcome, and any sort of pitch that induces a weakly hit ball is a good one — and one that can be replicated to greater effect going forward.

Slowly, Brown cobbled together strong starts and began to live up to the nickname given to him a few years earlier, when he was at Triple-A. The team had gathered at the airport at 3:30 a.m. to return home, and Brown was pounding a drink loaded with caffeine. Why, his teammate Pete Solomon asked, would he do that in the middle of the night when their flight wasn’t scheduled to land until 8 a.m.?

“Hey, man,” Brown said. “You put diesel in, you get diesel out. I’ve got stuff to do today.”

On that day, Diesel was born — and Brown’s velocity numbers support the sobriquet. Only Hunter Greene, Skenes, Skubal and Jose Soriano throw an average fastball harder than Brown’s 97.4 mph. It’s almost a tick and a half higher than last season, a function, Brown said, of a more mature routine. In addition to offseason work on mobility and strength gained through Bulgarian split squats, the 6-foot-2, 220-pound Brown relaxed his off-day weightlifting habit and ramped back his velocity in between-starts bullpen sessions from 92-to-94 mph to 86-to-88.

“His whole demeanor when he steps out there is different,” Pena said. “He shows up ready to dominate every time he’s about to take the mound. Every time he’s up there, you see him strutting around.”

It’s reminiscent of Verlander, whose cocksure mound presence is a defining feature. During Brown’s struggles, Verlander tried to remind him that his raw stuff was good enough to stop trying to execute perfect pitches and instead challenge hitters to hit his stuff in the strike zone. Brown’s walk rate this year is among the game’s best, and on pitches in the zone, hitters are batting .191/.200/.258 against him, good for the third-lowest OPS in the game.

“It goes one way or the other,” Hader said. “You feel sorry for yourself and play the victim or you figure out, ‘Hey, I got to do this to be where I want to be, and I want to stay here. I’ve got to be better.’ And that’s just the type of dude he is. I mean, go and look at the numbers over the last year.”

They remained sparkling Sunday during his first outing in Kansas City since the disasterpiece of 2024. Brown blitzed through six innings against the Royals, yielding one run and striking out seven, and solidified his case for AL Pitcher of the Month. Awards don’t really matter to Brown, though. This time last year, he worried about simply keeping his rotation spot.

No longer is that a concern. Diesel has arrived, carving lineups, snatching hitters’ dignity, writing one more chapter in the story of a naysayer-slaying, doubt-squashing triumph. Now, he’s learning to embrace something far more palatable than an ass whooping: success.