The Diamondbacks released lefty Joe Mantiply after his recent DFA, per their transaction log at MLB.com. Assuming he clears release waivers, he’ll be a free agent who can sign with any team tomorrow afternoon.
Mantiply, 34, has been a frequent presence in Arizona’s bullpen dating back to 2021. From ’21-’24, he pitched 198 1/3 innings with a 3.63 ERA, a 22% strikeout rate, a 6.1% walk rate, a 51.9% grounder rate, 50 holds and three saves. In 2022, specifically, he was one of the team’s most frequently used relievers in high-leverage spots.
The 2025 season has been an abject disaster for Mantiply, however. He fired a perfect inning in his first appearance of the season and immediately tanked thereafter. By the time Arizona optioned Mantiply to Triple-A Reno on April 19, he’d been tagged for a calamitous 13 runs in just 7 1/3 innings across eight relief outings. He got another look in mid-May and was quickly optioned again after surrendering four runs in 2 1/3 innings.
Even Mantiply’s time in Triple-A was generally a struggle. He allowed four runs in his first appearance with Reno and five in his final one. Those ugly outings bookended a strong run of 9 2/3 shutout innings, but the overall results were grim. In 9 2/3 MLB frames this year, Mantiply has a 15.83 ERA. He’s posted a 5.56 mark in 11 1/3 Triple-A innings.
Mantiply has always been a soft-tosser, but his fastball has bottomed out in 2025, averaging a career-low 88.2 mph. He sat 91.3 mph with the pitch back in 2021-22, when he was at his best, and was at 89.5 mph last year. He’s still filling up the strike zone, but doing so with diminished stuff has yielded diminished returns.
By all accounts, Mantiply is healthy at the moment. Teams are always in need of left-handed bullpen help, and Mantiply has a generally solid track record in the majors, so he ought to get another chance to turn his season around with a new club before too long. He’ll almost certainly need to pitch his way back to the majors on a minor league deal, however. He’s being paid $1.7MM this year, and the D-backs will remain on the hook for the rest of that salary — minus the prorated minimum for any team he spends with another club’s big league roster.