Rookie Spencer Schwellenbach compares favorably to a certain Braves Hall of Famer
The Atlanta Braves didn’t plan to promote their 2021 draft pick so early in his career, but he’s already served notice he’s here to stay.
The Braves selected Spencer Schwellenbach in the second round of the 2021 draft knowing he wouldn’t pitch until 2023. In July 2023, a shoulder injury cost him another six weeks on the shelf. He ended the year with 65 IP, and only 12 of those innings in High-A.
He threw 32 innings in High-A to start 2024 before he jumped to Double-A on May 15. Two weeks later, he was on the bump in Atlanta to make his first Major League start. It wasn’t great, but he threw strikes, and the day wasn’t too big for him. As the season went on, we learned no day is too big for him.
Most stories I’ve read say Schwellenbach had a rough start but improved when the calendar slipped to July. I don’t see it that way. The numbers say he had one bad start, allowing six runs to the Red Sox in his second start on June 2, but that’s the end of his rough outings. In his next 19 starts, Schwellenbach pitched to a 2.92 ERA, 0.912 WHIP, in 114 innings, striking out 118 and walking 20.
Why Schwellenbach has a ton of similarities to Braves legend Tom Glavine
When I told my editor that Schwellenbach reminded me of Tom Glavine, he said Glavine wished he could through a consistent 96mph fastball. That of course is true. However, that wasn’t where I saw the resemblance.
On the bump, Glavine and Schwellenbach share an important characteristic: a slow heartbeat. The game never gets too fast for them; it’s impossible to tell whether they have the game in their pocket or it’s a fight to make their pitches work. Neither pitcher let their body language betray them.
Glavine threw his 88-90 mph fastball 48% of the time, but his weapons were a 77-80 mph change he threw 45% and a low 80s slider. Batters beat those pitches into the ground or hit lazy fly balls to Andruw Jones.
Schwellenbach can throw his 96 mph four-seamer 29% of the time and batters WHIFF on it 20.5% of the time, so it is a weapon. He mixes three offspeed pitches - an 87 mph slider with a 27.9% WHIFF%, an 80 mph curve with a 40% WHIFF%, and an 85 mph splitter batters’ wave to as it goes by 46% of the time – to generate a 34.2% chase rate, 46% GB%, and a 4.6% barrel% that was the fourth lowest in the league.
Don't tell anyone, but I think #Braves righty Spencer Schwellenbach is pretty good pic.twitter.com/uJ5ZBdnsX7
— Chief_Fred (@FredEOwens) October 23, 2024
As a Brave from 1991 through 2002, Glavine allowed batters a .249/.312/.357 line with a .281 BABIP. In 2024, batters posted a .226/.271/.391 slash line with a .280 BABIP against Schwellenbach.
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.
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