You may not know by watching him, but beneath the surface, Diamondbacks pitching prospect Brandon Pfaadt has always been fueled by the doubts of his evaluators.

“That’s the story of my career,” he said.

It started at the end of high school when Division I recruiters were interested in his teammates but not him. Pfaadt landed at Bellarmine, a small Division II university in Louisville.

Working mostly as a reliever, Pfaadt’s collegiate numbers were unspectacular to start, though his sophomore ERA dropped more than two full runs from his freshman year. When his junior season came around, Pfaadt was deemed ready to start full-time. In his first five outings, he was better than ever, amassing a 3-1 record with a 1.38 ERA, 27 strikeouts and just four walks over 26 innings. Major league scouts took notice.

That was the spring of 2020. As it was for many of us, Pfaadt’s life was turned upside down by the pandemic. His March 7, 2020 start was his last with the Knights.

Months passed, Pfaadt’s college season was far behind and the MLB draft drew closer. Pfaadt expected to be selected between rounds two and six. Most years, that’s a guaranteed ticket to the big leagues, but not in 2020.

Due to revenue shortages, Major League Baseball and the MLB Players’ Association agreed to shorten the 2020 draft dramatically, trimming it from the usual 40 rounds to five. Pfaadt might get drafted — or, he could return to Bellarmine to build upon his abbreviated junior season.

The first four rounds came and went, and Pfaadt’s name was still on the board. Then, with the 149th overall pick — and with only 11 picks remaining in the draft — the Diamondbacks selected him as their fifth and final draftee.

Pfaadt has continued to prove evaluators wrong ever since, recently soaring into MLB Pipeline’s top 100 prospects list and now being viewed by most scouts as the best pitching prospect in the Diamondbacks’ organization. Out of the 148 prospects drafted before him in 2020, only 18 rank ahead of him on that top-100 list.

Pfaadt’s numbers speak for themselves. With the 2020 minor-league season cancelled, he officially made his professional debut in 2021. He posted an impressive 3.22 ERA and 1.01 WHIP with 160 strikeouts in 131.2 innings split between Single-A Visalia, High-A Hillsboro and Double-A Amarillo.

In 2022, Pfaadt has picked up where he left off in Amarillo, pitching to a 4.53 ERA with 144 strikeouts and just 19 walks in 105.1 before earning a promotion to Triple-A Reno on Aug. 2. In four starts with the Aces, Pfaadt has a sparkling 1.73 ERA, 0.73 WHIP, .136 opponent batting average and 26 strikeouts in four starts. He is on the doorstep of the big leagues.

If there is a knock on Pfaadt’s game, it’s that he has been home run-prone. In 138.2 career innings in Amarillo, he has given up 31 of them, and he has allowed four in 26 innings with Reno. That works out to a combined HR/9 of 1.91. For reference, the major-league average HR/9 is currently 1.08.

Most of Pfaadt’s home run woes can be explained by his pitching environment. His home ballparks in Amarillo and Reno are among the most home run-friendly parks in their respective leagues, both of which are already viewed as being hitter-friendly. Despite the challenge that presents, Pfaadt says that pitching in those parks has enhanced his development.

“If you’re playing in a graveyard and a mistake gets hit to the warning track, cool, that’s an out,” Pfaadt said. “But in Amarillo, that’s a home run.

“You’ve got to limit your mistakes, and you’re only going to limit them if you get hurt.”

Pfaadt throws a four-seam fastball that averages 93 MPH and touches 96 MPH, a low-80s slider and a mid-80s changeup. He also mixes in the occasional curveball and sinker. 

Not long ago, Pfaadt used his changeup solely to lefties and his slider solely to righties, but he has since mixed it up, throwing a roughly even mix of sliders and changeups against lefties and an occasional changeup to righties. With Pfaadt in Triple-A, StatCast data on his pitches is now available to the public — and it is eye-popping.

In four starts in Reno, the average spin rate on Pfaadt’s four-seam fastball is 2,489 RPM, and the average spin rate on his slider is 2,598 RPM. Relative to qualified 2022 major league starters, Pfaadt’s four-seamer spin would rank fifth in all of baseball, trailing only Corbin Burnes, Joe Musgrove, Julio Urías and Dylan Cease, while narrowly edging out Gerrit Cole. His slider spin would rank eighth.

Success in the majors involves more than high spin rates, but higher spin rates generally correlate with increased life, sharper movement and more whiffs. The fact that Pfaadt’s spin rates are in such elite company already makes it easy to dream of what he could become.

The elite spin on his fastball makes the pitch more likely to be effective up in the strike zone, which is where he usually tries to throw it. Pfaadt pegged heaters thrown too low and sliders not thrown low enough as the primary source for the home runs that have been hit against him. He is using those instances as a learning experience.

“It’s only making me better giving up those home runs,” Pfaadt said. “Like that pitch, that’s a mistake. You’re not going to get away with it in the big leagues, so why should I get away with it now?”

Since making his professional debut, Pfaadt has always had above-average command. His walk rate in Double-A this year was just 4.3 percent, and his 7.3 percent since moving to Triple-A is still very respectable.

There are worse problems to have in a young pitcher, but Pfaadt said he is actually prone to throwing too many strikes. He said that expanding the zone with two strikes has been a “key to this season.”

Whether Pfaadt will be among the Diamondbacks prospects to debut over the season’s final month remains to be seen. He is not on the 40-man roster, and the team is not at risk of losing him in the Rule-5 draft this winter. Other pitchers who are Rule-5 eligible this year could take precedence.

For now, Pfaadt knows that whether he gets called up to the big leagues this year or not, he has what it takes to make the most of it.

“I’m hoping for that to come, but everything happens for a reason,” Pfaadt said. “My journey has taught me that.”

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Top photo: Reno Aces/David Calvert Photography