During this past spring, the Philadelphia Phillies had some standout performances from some of their hopeful players in their auditions for the big league club. Among them included a young right-handed fireballer named John McMillon.
McMillon drove up the hype as he was exceptional in his brief spring showing, holding the opposition to just three hits and one run over six appearances. More importantly, he possesses a top-notch fastball that consistently hit triple digits, leading to his seven strikeouts in just six innings of work during spring training with the Phillies.
However, there was one caveat with McMillon that is wildly dominant. Despite his arsenal of nasty stuff, he would often have trouble with his control and command, as seen from his four walks he issued over six frames during the preseason.
John McMillon had plenty of hype during spring training, but his wild control has landed him on the development list
Well, that issue amplified once his 2025 minor league campaign began with the Phillies’ Triple-A affiliate Lehigh Valley IronPigs. In fact, the 27-year-old right-hander has been outright brutal with his control and command, so much that it has now landed him on the development list, according to his player page on MLB.com.
In just seven relief appearances with the IronPigs, McMillon has compiled a dismal 14.29 ERA, 3.18 WHIP, and given up a whopping nine earned runs on eight hits with 10 walks and 10 strikeouts in just 5 2/3 innings pitched. The strikeout rate has been awesome, but to see his walk rate exactly the same as his strikeout rate is a huge cause for concern for the promising fireballer. He will definitely need some proper adjustments to make him effective going forward.
As a former 11th-round pick by the Detroit Tigers back in the 2019 MLB Draft, McMillon made his major league debut with the Kansas City Royals in 2023. That season, he appeared in four games and allowed one run on one hit with eight strikeouts in four innings pitched. Last year, McMillon became a part of the Miami Marlins organization and made 10 relief appearances for the big league team, compiling a solid 1.50 ERA, 1.00 WHIP, along with 13 strikeouts in 12 innings of work.
As a result of his solid numbers and strikeout potential, the Phillies took a flyer on him by claiming him off waivers from the Marlins this past offseason. Until now, McMillon has come as advertised in terms of his wicked strikeout ability. But hopefully a trip to the development list can help straighten up his control to make him a lethal weapon to deploy out of the bullpen for the Phillies some time further down the road this year. After all, Philadelphia would more than welcome another potential elite arm to their relief corps, which has struggled to some extent coming out of the gate in 2025.