When pundits talk about 2024’s best rookie pitchers, the names most discussed were Japanese import Shota Imanaga, fireballer Paul Skenes, his Pirate’s rotation mate Jared Jones, and the Yankees’ Luis Gil. Meanwhile, Schwellenbach has been quietly having a superb season.
Schwellenbach ended the season with 127 strikeouts and 23 walks or 5.52 K/BB in 21 starts covering 123.2 IP. I thought that was an impressive ratio for a rookie, so I looked. In the Live-ball era (since 1920), 12 pitchers with at least 100 IP ended their rookie year with a K9/BB ratio greater than five.
- Masahiro Tanaka: 6.75
- Shota Imanaga: 6.21
- George Kirby: 6.05
- Roy Oswalt: 6.00
- Spencer Schwellenbach: 5.52
- Noah Syndergaard: 5.35
- Paul Skenes: 5.31
- Shane Reynolds: 5.24
- Chris Devenski: 5.20
- Matt Shoemaker: 5.17
- Shane Beiber: 5.13
- James Tallion: 5.00
If you look at pitching ratio stats, you’ll find K-BB%. The K-BB% stat is a pointer to pitcher efficiency; a larger gap indicates a pitcher throws more strikes – or pitches that look like strikes – and isn’t wasting his bullets.
Schwellenbach finished the year with a 20.5% K-BB%. Only 20 rookies with 100 IP in the live-ball era ended the season with at least a 20% gap. The Braves own Spencer Strider (29.7%) is first, Brandon Beachy (20.8% in 2011) is 15th, and Schwellenbach is 16th on the list.
One last note on K-BB%. Baseball’s seen 86 pitchers throw a total of 200 seasons with at least 100 IP and a 20% K-BB% gap. Mat Scherzer (11) has the most seasons, followed by Chris Sale, Clayton Kershaw, and Randy Johnson with eight.
The first pitcher to achieve it was Satchel Paige, who stuck out 152 batters in 145 innings and walked 30. The next player was Sandy Koufax, in 1962,1963, and 1965, so it’s an expansion era stat…unless you’re Satchel Paige.
How Schwellenbach's 2024 campaign compares to other great rookie seasons
Statistically, Schwellenbach’s the third-best rookie starter in the NL behind Skenes and Imanaga. The list ranks him fourth, but I put him ahead of Tobias Myers because his peripherals are better. As I was pulling data, I noticed a couple of rookie years that look a lot like Schwellenbach’s 2024.
In 2002, Mark Prior threw 116.1 innings over 19 starts in 20 games and ended the year with a 3.32 ERA, 122 ERA+, 3.16 FIP, and 1.166 WHIP.
In 2022, George Kirby threw 130+ innings in 25 starts and ended the year with a 3.39 ERA, 2.99 FIP, and 1.208 WHIP.
In 2024, Schwellenbach threw 123+ innings over 21 starts and ended the year with a 3.35 ERA, 3.29 FIP, and 1.043 WHIP.
That’s pretty good company.
The Braves handed the ball to Schwellenbach 21 times. He gave up two runs or less 13 times, allowed three runs four times, four runs three times, and in his only really bad outing gave up six runs in his second major league game. He pitched at least five innings in 19 games and threw seven innings four times.
He started six games when the team had lost at least two of the prior games and won four times. The only pitcher to win more and stop a losing streak was Sale, who won five times.
I’m not saying Schwellenbach is the next Mark Prior or Tom Glavine, that’s unfair to him and them. I am saying he’s a smart pitcher with excellent command of multiple pitches who used them well this year and isn’t awed when the crowd’s the loudest and the lights are brightest.
The Atlanta Braves rotation for 2025 looks very strong, with more talented arms in the pipeline.