Joe Mantiply Aiming For a Return to All-Star Form

Arizona Diamondbacks reliever Joe Mantiply made his 2025 Spring Training debut on Tuesday. The left-handed reliever is an integral part of the D-backs' bullpen, being heavily relied on by manager Torey Lovullo in 2024.

The former All-Star worked a solid inning as Arizona's opener against the Cubs, walking one hitter but allowing no runs to score. Mantiply spoke with media including Jack Sommers of Diamondbacks ON SI after his outing. "I felt pretty good. Fastball command was good. Off-speed was a little off, but that's what we're here to work on."

Mantiply had previously only thrown in bullpens and live at-bats against other Diamondbacks teammates. As Spring Training kicks into full gear more and more full time players, including the relief core will see game time. That was demonstrated today when he was joined on the field by A.J. Puk, Kevin Ginkel and Justin Martinez.

It isn't unusual for relievers to occasionally open a game in spring, but for Mantiply in particular, this is nothing new. He has opened 5 games for the Diamondbacks in the regular season over the past two years, and even started two playoff games, including game four of the World Series.

"It's fun. Honestly, any time I get to get the ball and I get to pitch, it's fun. There's good things about it. There's things I like and things I don't like. When it comes to having a routine, you have all the time in the world." Mantiply said.

The southpaw continued, "I also like sometimes getting a phone call in the seventh. That's just as fun. There are good things, things I like, and things I don't." Sometimes a leverage arm for Arizona, his work as a swingman is unusual, but his effectiveness, particularly against left-handed bats, makes him a great option.

When asked about specific things he's been working on Mantiply said, "Just trying to get my breaking ball back to what it was a couple years ago. Just get some confidence in it." 2022 was a special year for the lefty. Not only did he break out into a dominant reliever, but he earned an All-Star bid.

Naturally, Mantiply would aim to return to that dominant form, a season where he posted a fantastic 2.85 ERA. "The usage has dropped a little bit. I think it's just from a lack of confidence. Just trying to get back to that," the lefty said. "I'm not too worried about the shape. Just more about the command. Being able to throw it in the zone and take it out of the zone when I need to."

His 2024 season was somewhat dissapointing with only a 3.92 ERA, however his underlying metrics show that he pitched quite a bit better than this surface number. A 2.51 FIP surpassed even his All-Star campaign numbers, and his home run allowed rate dropped from the year prior.

Mantiply was relied on heavily by Diamondbacks manager Torey Lovullo last season, pitching 59.2 innings, only 1/3 of an inning shy of his career high total. Such a high workload is generally avoided if possible, but as a left handed specialist, he was often called when the team needed him most.

2025 should be a different story, with Kyle Nelson returning from injury, and A.J. Puk with the club for a full season, southpaws are now less of a luxury for the D-backs. Other lefty relievers in camp that could contribute during the season are Jose Castillo and Kyle Backhus. Blake Walston is a possible relief option, although he's still being stretched out as a starter for now.

When asked about the team's newfound pitching depth Mantiply seemed excited. "I think it's great. I feel like you can never have enough depth when it comes to pitching in general. The bullpen depth is huge."

The lefty continued, "You hope nobody ever gets injured, but the longer you play this game, you see it's unavoidable at times. Having good depth for that is huge. I don't think we're too worried about it from a player's standpoint."

A point of competition in the Diamondbacks organization this spring is for the role of closer. While there was a possibility that the team would seek out a closer on the market this winter, things never quite materialized. Instead GM Mike Hazen acquired former back end reliever Kendall Gravman who is making a return from shoulder surgery.

Mantiply spoke on his opinions on the 9th inning role, saying "We've got multiple guys that can do that job. At the end of the day, that decision is out of our hands. We just got to take the ball."

"It's quite a number of guys." the lefty continued. "It's comforting. It can be tough sometimes when you're the only guy down there. You got to fill multiple roles. The more the merrier. Having more guys down there frees you up a little bit. You can focus on more of a honed-in role and hopefully get some help out of those guys."

Joe Mantiply will once again be a big contributor for the Diamondbacks in relief. His attitude toward the 2025 season seems optimistic for a return to his best self but also feels realistic in that the team has a lot of options. However things go, the Mantiply is a name, and an arm, that can be relied upon.

As the season draws near, with less than a month until opening day, make sure to stay tuned to Diamondbacks ON SI as we bring you the latest, in D-backs news, breakdowns, and in-depth analysis.

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