Phillies’ rookie reliever is turning into the stud we always expected him to be

Entering the 2024 season, the Philadelphia Phillies' bullpen was highly regarded and ranked as one of the top relief corps in baseball by MLB.com. Through this point in the season, the bullpen has lived up to the hype. Relievers like Jeff Hoffman, Matt Strahm and José Alvarado have pitched about as well as anyone could have hoped.

One of the bullpen's biggest success stories from the 2023 season was the rise of right-handed reliever Orion Kerkering. His ascension through the organization's minor leagues was almost unprecedented as he played for all four minor league affiliates before being called up last September.

As a late-season callup, his role was a bit undefined as the Phillies marched their way toward another postseason, but the expectations were sky-high for Kerkering, who had posted a 1.51 ERA and 79 strikeouts in 53 2/3 innings in the minors. During the regular season, he pitched just three innings for the Phillies and accrued a 3.00 ERA with six strikeouts.

Through seven postseason appearances, Kerkering pitched to a 3.38 ERA but is widely remembered for faltering in the NLCS when he seemed to lose the feel for his sweeper and didn't utilize his electric four-seamer. That's something the 23-year-old corrected heading into 2024.

Phillies’ rookie reliever is turning into the stud we always expected him to be

Kerkering started the season on the IL after being hit by the flu in spring training and needed time to ramp up his throwing activity. He made his 2024 debut on April 14 against the Pittsburgh Pirates. Since that time, the California native has met and perhaps exceeded expectations.

In 22 2/3 innings logged through June 11, the former fifth-round pick has a 1.19 ERA and a 0.84 WHIP while striking out 24 hitters and walking just four. After pitching a full season in the minor leagues, Kerkering may have been a bit gassed by the time September and October rolled around last year. The hope is that he can maintain his fastball velocity and continue to use it despite losing the feel late last season.

Kerkering's fastball usage has helped fuel his solid start

One of the biggest changes we've seen with Kerkering is the increase in his four-seam fastball usage as compared to the end of the 2023 season. The Athletic's Matt Gelb notes that during his time with the Phillies last year, they had Kerkering throw his sweeper an astounding almost 70 percent of the time (subscription required) because the pitch has movement that not many other major league pitchers had on the pitch.

This season, things are different. The plan was to incorporate his high-velocity fastball into the mix more often so hitters were not always sitting on the breaking ball. Kerkering has successfully mixed in his four-seamer more often this season. He has thrown his sweeper just over 56 percent of the time while hurling the four-seamer just over 33 percent of the time while mixing in the occasional sinker. He's still using the sweeper heavily but can also command and establish his 98 mph fastball.

The velocities on his pitches haven't changed much from last season, but the usage of the pitches has made a difference. Kerkering is using his talent and electric arm to keep hitters more off-balance. As he matures and gains more experience, he should be considered one of the top arms in the Phillies bullpen. He has the stuff and the arm to be a dominating major league reliever.