Unsung Phillies reliever looks poised for 2026 breakout with secret weapon

Many of the Philadelphia Phillies relievers are competing for big roles on the team. José Alvarado and Jhoan Duran appear to be the team's primary options in the eighth and ninth innings, respectively, in close games where Philadelphia isn't trailing by much or has a narrow lead.

Jonathan Bowlan, whom the club acquired for Matt Strahm in a trade with the Kansas City Royals in December, is one pitcher worth paying attention to in spring training. Philadelphia cleared nearly $7 million in payroll with the move, according to MLB.com's Todd Zolecki, but Bowlan could be much more than a payroll-saving acquisition.

Especially if he uses his sinker more often.

Get ready for Jonathan Bowlan's sinker to fuel breakout in Phillies' bullpen this season

As noted by Mikey O'Connor, Bowlan's 96 mph sinker ranked fifth with 4.3 RV/100 (run value per 100 pitches) in 2025. That was among pitchers with at least 50 sinkers thrown. Among those with 100 pitches thrown, Bowlan tied for first. It was his third-most used offering (17 percent usage), as he also throws an excellent four-seam fastball (33 percent) and slider (31 percent).

Bowlan's advanced metrics from last year show why he could be effective out of the bullpen this year. His 95.7 mph four-seamer velocity ranked in the 72nd percentile. He held hitters to an excellent 87.3 mph exit velocity and had an elite 33.7 percent whiff rate. His hard-hit rate of 36.8 percent and ground ball rate of 49.6 percent are also considered well above average.

Among Bowlan's two most used pitches, his four-seamer generated a 43.5 percent whiff rate while his slider had a 40.2 percent whiff rate. He generated just a 17.6 percent whiff rate with his sinker but held hitters to a stingy 10.7 percent hard-hit rate and an insanely low 74.6 mph average exit velocity. It's no wonder opponents hit just .161 and slugged .161 against the pitch.

Early in the first full week of spring training workouts, Bowlan found success against two of the Phillies' best hitters. He compiled back-to-back strikeouts of Trea Turner and Kyle Schwarber. Bowlan has impressive pitches that could make him a reliable option for manager Rob Thomson to use out of the bullpen in 2026 (subscription required).

The Phillies may end up receiving help in their bullpen from the under-the-radar Bowlan, who's still inexperienced in the majors compared to several pitchers in the bullpen. Considering he gradually improved some of his statistics over his last two seasons in the minors, he's worth watching to see if he can build on his 2025 performance with the Royals.

The 29-year-old only pitched in three MLB games, two of them starts, during the 2023 and 2024 seasons with the Royals. He split 2023 between Double- and Triple-A, making 24 appearances (21 starts) with a 7-11 record, a 5.91 ERA, a 1.58 WHIP, 105 strikeouts, and 45 walks in 102 innings.

In 2024, Bowlan made 16 starts in 35 appearances with Triple-A Omaha, finishing with a 12-4 record, a 4.67 ERA, a 1.35 WHIP, 98 strikeouts, and 34 walks in 104 innings pitched. Last year he appeared in 24 games for Omaha, all in relief, going 3-0 with a 2.25 ERA, a 0.94 WHIP, 45 strikeouts, and 11 walks in 36 innings.

Bowlan earned his most extensive stint in the majors last season. He appeared in 34 games, making one start with Kansas City. He had a 1-2 record, a 3.86 ERA, a 1.22 WHIP, 46 strikeouts, and 17 walks in 44 1/3 innings.

Bowlan is projected to compete with Brad Keller, Tanner Banks, and Orion Kerkering for pitching time in a middle relief role during the regular season. Keller and Kerkering throw right-handed like Bowlan, so it will be a battle between those three beginning in spring training and early in the regular season to see who receives a bigger role later in games. The MLB season is a long grind, so Bowlan may work his way up to earning more responsibility or receive an opportunity due to injuries in Philadelphia's bullpen.