Major League Baseball

What makes Astros rookie Hunter Brown so good? The most balanced pitch mix in baseball

Updated May. 5, 2023 9:20 a.m. ET

In another generation, Astros rookie Hunter Brown’s heater — which averages 96 MPH and has maxed out at 99 — would stand out as exceptional, particularly for a starting pitcher. In 2023, with velocity at an all-time high across every level of baseball, Brown’s fastball is hardly one of the most noteworthy things about him.

At least, not on its own.

Even in today’s game, Brown’s velocity is still considered above average. His 95.8 mph average four-seamer puts him in the 85th percentile for average fastball velocity in MLB. But "top pitching prospect throws hard" is simply not the eye-catching headline it used to be. Rather, what makes Brown extraordinary is that his high-90s fastball is arguably his third-best pitch.

With Justin Verlander departing in free agency, the 24-year-old Brown was expected to play a crucial role this season as the de facto replacement in the rotation for the future Hall of Famer. But the Astros rotation has already suffered several injuries in the early going, further heightening the need for Brown to deliver on the hype surrounding him. Lance McCullers Jr. still hasn’t made a start this season as he works his way back from a February elbow strain. José Urquidy just left his most recent start with shoulder discomfort. The very next day, Luis Garcia faced one batter before departing with elbow pain. Suddenly, Brown has been thrust into the No. 3 starter spot behind Framber Valdez and Cristian Javier.

Thus far, he’s been more than up for the task. Brown has been the best rookie pitcher in MLB by fWAR, posting a 2.60 ERA over his first six starts of the season with 36 strikeouts in 34.2 innings of work. His 140 batters faced without yielding a long ball is tied with Sonny Gray for second-most in the majors behind only Gerrit Cole's 177. Brown has still yet to allow a home run in his MLB career, a 58.2 inning streak that includes his first 20.1 innings last September plus another 3.2 playoff frames in October.

A fourth-round pick in 2019 out of Wayne State University in Michigan, Brown already stands out among big leaguers for his collegiate background — roughly 3% of active MLB players were drafted out of a Division-II school, with other notable D-II alumni including J.D. Martinez, Joe Ryan, Josiah Gray, and Brown's Astros teammate Chas McCormick.

For any pitching prospect, especially at the amateur level, questions around an individual’s likelihood of starting instead of relieving long-term are primarily centered on three criteria: delivery, command and depth of arsenal. Brown burst on the scouting radar at Wayne State due to his high-end velocity, which he held deep into outings and paired with a hard slider. The stuff was undeniable, and the delivery was fine, but it was still just two pitches and he was spraying them — Brown walked 4.1 batters per 9 innings in the spring, and another 18 batters in his first 23.2 innings in pro ball after signing.

Boasting only a pair of go-to pitches and command issues all while coming from a smaller school, scouts were quick to wonder if the rotation would be a viable option for Brown long term. It’s why most of his scouting reports from the first few years of his career ended with some version of what MLB Pipeline wrote entering the 2021 season: "In order to remain a starter at higher levels, Brown will have to add some polish. He needs to refine a changeup that gets too firm and repeat his delivery more consistently so he can locate his pitches better. If he winds up in the bullpen, his fastball/curveball combination could make him a high-leverage option."

But something interesting happened with Brown as he climbed the Astros’ minor-league ladder and developed in an organization known for maximizing its pitchers. Rather than focus on mastering a changeup to round out a traditional fastball/breaking ball/off-speed repertoire, the 6-foot-2 right-hander instead began to emphasize a second slower breaking ball with more depth than his high-velocity slider.

This is where Brown’s near-elite velocity does come back into play as a key ingredient. If the purpose of a third pitch is to keep hitters off balance due to a differentiation in velocity, the only way a pitcher can throw multiple effective breaking balls is to have significant separation in their velocities. With Brown’s heater already in the upper-90s, he had room to shift his slider up into a low-90s velocity band while shifting down the new curveball to the low-80s. Voilà — three distinct pitches. No change necessary.

Now, Brown isn’t the only starting pitcher to successfully eschew a changeup in favor of alternative secondaries. Clayton Kershaw is going to be a first-ballot Hall of Famer having thrown almost exclusively fastballs, sliders and curveballs over the course of his career. Better comparisons for Brown would be Zack Wheeler or Dylan Cease, both of whom throw awfully hard and lean heavily on both sliders and curveballs when they aren’t throwing fuel.

But it’s not just that Brown throws two different breaking balls — it’s that his three-pitch mix is balanced to a degree unlike any other starter in baseball.

Brown has thrown 573 pitches across six starts in 2023. Here’s the breakdown of those 573 pitches:

200 sliders (34.9%) — AVG 92 mph
180 four-seam fastballs (31.4%) — AVG 96 mph
179 curveballs (31.2%) — AVG 83 mph
14 splitters (2.4%) — AVG 89 mph

Brown does throw a traditional off-speed pitch in a splitter. He hasn’t thrown it very often, but he has registered three strikeouts with it, including a gnarly whiff from Brandon Lowe. That’s another weapon he may start to use more against left-handed hitters as the season goes on.

For the most part, though, it’s three pitches deployed in stunningly equal fashion. In fact, Brown is the only starting pitcher in baseball to rely on three different pitches at least 30% of the time. Alek Manoah (29% four-seam, 31% sinker, 28% slider), Patrick Sandoval (27% four-seam, 31% slider, 29% changeup), Corey Kluber (28% sinker, 26% cutter, 28% curveball) and Edward Cabrera (28% four-seam, 34% changeup, 26% curveball) are the closest comparisons in terms of pure balance, but their repertoires are markedly different from Brown’s.

Hitters facing Brown are forced to reckon with a nearly equal chance of dealing with three different high-octane pitches: a slider that is harder on average than any other in MLB, a curveball with vicious vertical drop that is also harder on average than all but five curveballs, and a good old-fashioned heater that he can blow right by you at the letters. And if he breaks out the rare splitter, good freakin’ luck.

The best start of Brown’s year so far wasn’t just a personal best — it was the best outing anyone's had against the juggernaut Rays this season. Brown twirled seven scoreless innings, yielding just two hits and striking out eight.

The pitch breakdown in that outing? Forty-one sliders (43%), 30 knuckle curves (32%), 21 four-seamers (22%) and three splitters (3%). Who needs a changeup? Pitchers in 2023 use 96 mph fastballs as their so-called "third pitch." It’s a new age.

Though he’s clearly made strides in recent years, command is still a weakness for Brown. We saw it in his most recent start when he walked five Giants and struck out just four in his first loss of the season. His walk rate is still over 10%, which is above the league average of 8.8%. But if Brown’s stuff is this good — and he can suppress hits to the point where the frequent free passes don’t hurt as much — he can certainly succeed as a starting pitcher. Just ask Cease and Shohei Ohtani, both of whom have career walk rates around 11%.

A year ago this time, Brown was in the early stages of a dominant run in Triple-A. The numbers spoke for themselves, but they stood out even more in the context of the ridiculously hitter-friendly Pacific Coast League he was pitching in. Among 50 pitchers who threw at least 70 innings in the PCL in 2022, Brown posted the lowest ERA (2.55) and FIP (3.27), second-lowest WHIP (1.07) and highest strikeout rate (31.5%) in a year when the league-wide ERA was 5.82.

As the injuries pile up on its staff, the good news for Houston is that Brown isn’t the only pitching prospect who has shredded the challenging PCL over the past year. You may not recognize their names, but take a look at what guys like Brandon Bielak, JP France and Shawn Dubin have done in Sugar Land, especially last season. There’s real depth there.

But while those guys could reasonably weather the storm as the familiar faces rehab on the IL, only Brown offers such high-end upside. He has the potential to legitimately raise the ceiling of the entire team, not just now but come October.

Jordan Shusterman is half of @CespedesBBQ and a baseball writer for FOX Sports. He has covered baseball for his entire adult life, most notably for MLB.com, DAZN and The Ringer. He's a Mariners fan living in the Eastern Time Zone, which means he loves a good 10 p.m. first pitch. You can follow him on Twitter @j_shusterman_.