The Braves seem to have a new pitching strategy -- cornering the market on dominant right-handers named “Spencer S.”
There’s Spencer Strider, the mustachioed fireballer with a knack for strikeouts, having fanned an MLB-best 281 hitters as an All-Star in 2023. There’s also Spencer Schwellenbach, a 24-year-old quickly establishing himself as one of baseball’s best young pitchers. Through five starts, heading into Sunday’s matchup against the Diamondbacks, Schwellenbach has a 2.56 ERA and a 3.12 FIP. He’s building off a 21-start rookie season in which he posted a 3.35 ERA and 3.29 FIP following a surprise callup last May. Since his debut, Schwellenbach has accumulated 3.2 fWAR -- 14th most of 99 qualified starting pitchers.
Braves fans are still waiting for the two phenoms to share a rotation: Strider missed most of last year following elbow surgery, and he’s back on the IL with a hamstring strain less than a week after his season debut. For now, Schwellenbach is the lone “Spencer S.” on the mound, and he brings a lot to the table that not even Strider does.
Strider arrived in the Majors as a two-pitch pitcher relying heavily on his four-seam fastball. Since the start of the 2022 season -- Strider’s rookie campaign -- only four pitchers have thrown a greater percentage of four-seamers than Strider (min. 500 pitches thrown). While he’s since added a changeup and a curveball, Strider can succeed on the back of his fastball because of the pitch’s elite velocity and rising action. There’s also the wipeout slider, responsible for 139 strikeouts in 2023 -- the most on an individual pitch type, for any pitcher. He has overpowered hitters from the jump.
Schwellenbach did, too -- just in a different way. Well, really, six different ways.
Schwellenbach unleashed five different pitches in his MLB debut last May, added a sixth offering in his second start and hasn’t looked back since. As far as consistently using six different pitches -- four-seamer, slider, splitter, sinker, curve, cutter -- the versatility of his arsenal is nearly unmatched.
SPs using at least six different pitches 9% of the time, 2025
- Walker Buehler (30 years old)
- Zach Eflin (31)
- Clay Holmes (32)
- Merrill Kelly (36)
- Michael Lorenzen (33)
- Spencer Schwellenbach (24)
- Tomoyuki Sugano (35)
- Zack Wheeler (34)
Even in this group, Schwellenbach stands out.
Holmes, an All-Star closer, added three new pitches this offseason while transitioning back to starting pitching. Kelly integrated a sixth pitch into his arsenal in 2023, as a 34-year-old with four years of experience in the KBO. Wheeler -- who looks to add a new pitch every year -- didn’t have a six-pitch repertoire until 2018, five years after his MLB debut. Sugano is a rookie, but only in MLB, having first spent 12 years in Japan’s NPB.
As for Schwellenbach? He’s thrown all of 297 professional innings and spent more time at the University of Nebraska as a shortstop than a pitcher -- partially due to an elbow injury, partially because he posted an .829 OPS. Schwellenbach turned in an All-American season out of the bullpen as a junior, prompting the Braves to make him a second-round pick in the 2021 MLB Draft. Soon after, he underwent Tommy John surgery, and didn’t throw his first professional pitch until 2023.
Still, he arrived in the Majors (after skipping Triple-A) with six pitches that he uses frequently. Even in an era of pitching when everyone is adding a new pitch, few pitchers tout an arsenal as consistently diverse.
As a rookie, Schwellenbach was one of just four starting pitchers to record a positive or neutral Run Value with at least five different pitch types (min. 200 pitches each). The other three -- Wheeler, Seth Lugo and Logan Gilbert -- all finished inside the top six in Cy Young Award voting, with Wheeler and Lugo finishing as runners-up.
Amid an encouraging start to 2025, Schwellenbach currently has four pitches grading out above 0 on the Run Value scale. More importantly, he’s made some slight tweaks to his mix, giving reason to believe that his sophomore season may get even better.
1. He altered his sinker usage
Sinkers are en vogue again, so long as they’re used correctly. What does a good sinker look like? Let’s watch Schwellenbach.
As MLB.com’s Mike Petriello noted, pitchers are throwing hard sinkers with plus arm-side movement, running them inside to same-sided hitters. On top of that, nearly half of all sinkers are gaining extra or unexpected movement from seam-shifted wake -- a phenomenon in which pitchers use the seams of the ball to catch air on the way to the plate.
Schwellenbach’s sinker fits the bill. Based on Stuff+ -- which grades the physical characteristics of a pitch -- Schwellenbach’s 114 mark is tied for the fifth-best sinker of any qualified starting pitcher.
He’s maximizing the pitch with elite location, too. As a rookie, Schwellenbach threw his sinker equally to left-handed hitters and right-handed hitters. This year, he’s thrown just four sinkers to a lefty, while quadrupling the pitch’s usage rate against righties (7.3% to 27.3%).
Toss in upper-90s velocity and seam-shifted movement, and it’s no surprise that Schwellenbach’s sinker has taken a tremendous leap.
Batters vs. Schwellenbach’s sinker, 2024 vs. 2025
- 2024: .319 wOBA // .315 xwOBA // 88.3 mph EV // 9.4 Whiff%
- 2025: .199 wOBA // .269 xwOBA // 83.8 mph EV // 24.2 Whiff%
2. His four-seamer is becoming a weapon, too
In January, Schwellenbach told Rob Friedman of Pitching Ninja that his four-seamer had “bad shape,” which prompted him to work on a sinker and a cutter. But this year, the pitch is getting more vertical movement than it did in 2024. He’s gained 2.0 inches of induced vertical break -- the amount of break a pitcher generates from how he spins a ball, removing gravity from the equation. Instead of having below-average vertical movement, Schwellenbach’s 4-seamer is now roughly average.
A combination of other traits -- a lower than average release point, plus velocity, and elevated location -- help Schwellenbach create a flat vertical approach angle, a deceptive tool that helps fastballs play up. That’s turned his four-seamer into a swing-and-miss option.
Whiff Rate on Schwellenbach’s 4-seamer
- 2024: 80th in whiff rate (20.3%) min. 100 4-seamers thrown
- 2025: 12th in whiff rate (29.6%), min. 25 4-seamers thrown
In a start against the Marlins on April 4, Schwellenbach generated 11 whiffs with his four-seamer -- three more whiffs than he’s ever had with the pitch in a single start.
Yet fastballs are only a portion of Schwellenbach’s diverse arsenal. For such an inexperienced pitcher, he’s shown an impressive ability to adjust his pitch usage on a game-by-game basis. Before carving up Miami’s lineup with four-seamers, Schwellenbach threw a season-high 20 splitters to dominate the Padres. A few starts later, the Phillies smashed a couple of hits off his sinker, so he pivoted, recording five strikeouts on a season-high 24 sliders. There’s a readily apparent comfort level with all six pitch types.
Beyond the pure stuff, it’s the flexibility and versatility of his repertoire that should prime Schwellenbach for more success in 2025.