The Philadelphia Phillies have been at odds with their bullpen since the 2025 season kicked off. The dynamic group from last year has changed with some different faces, while the returning faces looked to step up in their role for the 2025 club and beyond.
With the Phillies losing Jeff Hoffman and Carlos Estévez in free agency, the Phillies needed more reliable arms to fill those holes. The Phillies' 24-year-old right-hander Orion Kerkering is an exciting young arm who could be the next star in the making. Kerkering broke out in 2024 after flying through the minors in 2023, so the narrative was looking more like 2025 was set up to be his best year-to-date, according to MLB.com's Todd Zolecki.
The prophesying has for now come to a halt, as Kerkering has pitched to a 4.85 ERA and 1.62 WHIP in his first 15 games of 2025. He doesn't even look like the same pitcher and according to an MLB insider, it could be the Phillies setting him up for failure and the reason he has fallen flat through the first month of baseball.
Did the Phillies break Orion Kerkering by messing with his best pitch?
Jayson Stark of The Athletic recently went on 97.5 The Fanatic and talked about the belief among pro scouts that the team has changed the look of Kerkering's sweeper. Kerkering was a feared pitcher out of the bullpen, but now struggles to get the big outs and strand runners on base, leading to blown leads, per MLB.com's Paul Casella.
"When I look at Orion Kerkering, I think he's fixable," Stark said. "But I did talk to two scouts this week who cover the Phillies, and they think that the Phillies have somehow messed up his slider because it has a slightly different shape now, so the hitters see it so much better."
Stark references a worrisome dip in whiff rate for Kerkering's sweeper. According to Statcast, the 2023 version of the sweeper registered a 40.0 percent whiff rate, albeit in only three games. Through 63 innings in 2024, the whiff rate came in at a more modest 31.1 percent. Through 14 outings so far in 2025, that number has plummeted to 23.3 percent.
The signature pitch that Kerkering relied on has also allowed a .452 slugging percentage in 2025. His sweeper only allowed a .306 slugging percentage in 2024. Even with the drop in production, Kerkering has surprisingly utilized the sweeper more in 2025, throwing it 60.4 percent of the time, compared to 55.7 percent last year.
The higher hit rate coupled with the loss of command has also lowered his strikeout percentage to a career-low 20 percent, per FanGraphs. That can't be a sustainable number for a potential late-inning reliever for the playoff expected Phillies.
The 2025 season is young enough that Kerkering has time to figure it out. The Phillies could have changed his pitches in hopes of making his stuff more elite. It hasn't worked so far, but tinkering can take time to iron out. The Phillies are slowly climbing out of the basement of bullpens across MLB, and the hope is Kerkering can be an arm to lead the team into a more sustainable group as the season carries on.