Last season, Arizona Diamondbacks' rookie Brandon Pfaadt entered the year as one of the top pitching prospects in baseball. Pfaadt was a consensus top 100 prospect, as FanGraphs, Baseball America, MLB Pipeline, and Baseball Prospectus all had him on their list. FanGraphs rated him the highest at 23. His season had a ton of ups and downs, but he could be the biggest candidate in baseball to break out next season, at least among pitchers.
Pfaadt’s bottom line wasn’t all that impressive. He had a 5.72 ERA, 5.18 FIP, and 1.41 WHIP through 96 innings. Pfaadt had a respectable 22.3% strikeout rate and an outstanding 6.2% walk rate. But there was one clearly defining feature of his season where most of his struggles originated.
He had a horrific home run rate. Pfaadt allowed 13 home runs, resulting in a HR/9 rate of 3.13. He allowed more walks (11) than home runs. Granted, a 21.7% HR/FB ratio indicates some positive regression, but allowing over three home runs per nine innings will never result in good numbers.
However, Pfaadt looked great from August onward. Through his final 58.2 innings of the year, Pfaadt worked to a 4.14 ERA, 3.89 FIP, and 1.26 WHIP. The rookie right-hander upped his strikeout rate to 25.6% while lowering his walk rate to 6%. However, the biggest improvement was his HR/9 rate, which dropped to a significantly more manageable 1.35-per-9 rate. His underlying numbers also painted a positive picture with a 3.89 xFIP and 3.81 SIERA.
Of course, Pfaadt would then go on and dominate in the Postseason. He started five games and pitched 22 innings, only allowing eight earned runs, striking out 26 batters, and only allowing five to reach via free pass. His K:BB ratio clocked in at 5.20. This resulted in an ERA of 3.27 and a WHIP of just 1.09. If you combine Pfaadt’s second-half and Postseason stats, you get an ERA of 3.91.
Pfaadt’s stuff is undeniably good. He throws around 93-95 MPH and approaches 2500 RPM. His change-up clocked in around the upper 80s with above-average movement. His sinker also displayed good movement, and both his slider and curveball showed some promise last season. Command was by far the best part of his game. Pfaadt’s velocity also plays up because of his release point extension, which adds about one whole MPH to his stuff.
Pfaadt’s 2024 season will be his age-25 campaign. Considering how well he did after August, in the Postseason, and his prospect status going into the year, I think he’s one of, if not the biggest breakout candidate among pitchers next year. He’s overshadowed by Zac Gallen, Eduardo Rodriguez, and Merrill Kelly, but don’t be shocked if Pfaadt is better than some of them next year.