Diamondbacks Release Former All-Star Reliever

On Sunday, the Arizona Diamondbacks released left-handed reliever Joe Mantiply, according to their transaction log. The move comes just days after he was designated for assignment back on May 30.

Mantiply's 2025 season, had begun in exceptionally poor fashion. He never truly recovered, and his numbers were simply too poor to overlook. In just his second outing of the season, he was roughed up for three runs while recording just one out.

Mantiply was sent down to Triple-A Reno on April 19 after his first bout of difficulty. He made 10 appearances with the Reno Aces, pitching to a 5.56 ERA and allowing nien runs (seven earned) in 11.1 innings. He gave up four homers in his minor league stint.

Upon recall, the left-hander gave up four more earned runs in just 2.1 innings. He allowed at least one earned run in his last six outings with Arizona — four of which were multi-run affairs. That earned him an ugly 15.83 ERA, a number that could no longer be ignored.

His velocity had taken a dive as well. Though Mantiply was never one to blow away hitters with his fastball, his trademark sinker had fallen all the way to 88 MPH. As the velocity dipped, so did the command. Opponents hammered that sinker to a 1.143 slugging percentage, and his curveball hardly fared better at .955.

But despite how ugly the 2025 season became, the veteran southpaw had been an undeniably valuable member of a Diamondbacks' bullpen that has seen its fair share of hardship over the years. He was one of the lone bright spots in a 2022 relief corp, and provided consistency against both left- and right-hand batters.

His 2022 heroics earned him Arizona's lone All-Star berth, as he went on to throw an excellent 2.85 ERA season over a workhorse load of 60 innings. Though his raw results in the 2023 and 2024 seasons were not nearly as sparkling, his underlying metrics usually told the story of a much more proficient arm.

Mantiply had a knack for coming through in big moments, often relied upon to face some of MLB's most elite left-handed hitters — names like Shohei Ohtani, Freddie Freeman and Bryce Harper. He even made two starts in the 2023 Postseason as an opener, including Game 4 of the World Series.

But at 34 years old, his time with the Diamondbacks' organization is now done. He'll be eligble to sign with any club that may be interested.

Though Mantiply certainly did not do his team any favors in the early goings of 2025, he's always been a true professional, a positive clubhouse presence and an arm that manager Torey Lovullo was able to rely on in some of the darker eras of the D-backs' pitching staff.

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