In 2019, Brandon Pfaadt worked primarily as a reliever at Bellarmine, a then-Division II university in Louisville, Kentucky. Entering 2023, he is widely viewed as the best overall pitching prospect in the Diamondbacks organization, and he could break into the big leagues as soon as Opening Day.

“He just keeps getting better and better,” Diamondbacks farm director Josh Barfield said. “First year we’re like, oh man, this guy’s kind of interesting. He can throw strikes, has a pretty good changeup. The next year, it’s like, alright, now he’s throwing harder and the breaking ball’s getting better and…you know, Amarillo is not an easy place to pitch and he does just fine there. Then he goes to Triple A, which has even better hitters and is a tough place to pitch, and he’s dominating there.”

The Diamondbacks selected Pfaadt in the fifth and final round of the shortened 2020 draft. The right-hander’s arsenal primarily consists of a fastball, slider and changeup, also mixing in the occasional curveball and sinker.

At 6-foot-4, 220 pounds, Pfaadt has the build of a durable starting pitcher and excellent command that propels him to pitch deep into games. Many scouts view the right-hander as a mid-rotation starter, but his eye-popping minor-league numbers indicate he may be capable of even more. His career has already been defined by proving his evaluators wrong.

Pfaadt spent the first three months of the 2022 season with Double-A Amarillo, which, based on Baseball America’s minor-league park factors, was the most challenging pitching environment in all of minor-league baseball. In spite of that, Pfaadt had a respectable 4.53 ERA and 1.25 WHIP (league average ERA and WHIP for the Texas League in 2022 were 5.11 and 1.49, respectively). His 32.2 percent strikeout rate and 4.3 percent walk rate were both elite.

In August, Pfaadt earned a promotion to Triple-A Reno, where he spent the rest of the season. In 61.2 innings over 10 starts, the 24-year-old went 5-1 with a 2.63 ERA, 0.99 WHIP and 74 strikeouts. Relative to the league average 5.40 ERA and 1.51 WHIP across the Pacific Coast League, Pfaadt’s numbers were off the charts.

By the end of the season, Pfaadt had amassed 218 strikeouts — the most by a minor-league pitcher in a single season in more than 20 years. He also led all minor-league pitchers with 167 innings pitched, which should eliminate the possibility of facing significant inning restrictions in 2023.

Pfaadt’s best pitch is arguably his four-seam fastball. Sitting at 93 with occasional showings of 96, Pfaadt’s four-seamer is most effective when thrown up in the zone, where it generates plenty of swing and miss due to an exceptional spin rate.

Through his first four starts in Reno this season, Pfaadt’s fastball averaged 2,489 RPM. For reference, among major-league pitchers who threw 2,500 or more pitches in 2022, Pfaadt’s spin rate would rank fifth in baseball. He’s in pretty good company, too.

High spin rates do not guarantee success, but high-spin four-seamers generally appear to have more upward ride and are therefore more effective up in the zone. Pfaadt’s fastball command is excellent, and he’s able to throw it where he wants to more often than not.

Pfaadt’s slider is arguably his best secondary pitch. Like his heater, Pfaadt’s slider benefits from a high spin rate that gives the pitch increased movement. While Pfaadt used the pitch almost exclusively against righties in the past, he has started to use it more to lefties.

Pfaadt’s primary out-pitch to lefties is his changeup. Some scouts say the pitch has the tendency to flatten out at times and is less consistent overall than his slider and heater. Nonetheless, the pitch has proven to be a trusty part of Pfaadt’s arsenal.

If there is any flaw in Pfaadt’s game, it is that, ironically, he can be guilty of throwing too many strikes at times, to the point that opposing hitters can get too comfortable in the box. In 2022, Pfaadt focused on expanding the zone more with two strikes and showed a lot of growth in that area.

Still, Pfaadt did allow 28 homers in 2022, and cutting down on the long ball will be a point of emphasis moving forward. Granted, he may always be homer-prone given how much he likes to work up in the zone.

Ultimately, Pfaadt has all the tools to be a big league starter for a long time, and he could join the D-backs’ rotation as early as Opening Day 2023. Given how much he has already surpassed expectations in the past, don’t be surprised if Pfaadt turns heads again next year — this time in the big leagues.

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Top photo: Reno Aces/David Calvert Photography