The Arizona Diamondbacks have started addressing their bullpen. ESPN’s Jorge Castillo reports that the Diamondbacks have agreed to a minor league deal with former Yankees reliever Jonathan Loaisiga. The deal includes an invitation to big league Spring Training.
Loaisiga, 31, is the type of upside play general manager Mike Hazen should make to improve the bullpen. The right-hander still features premium stuff, sitting 96.8 MPH on his sinker. If healthy, he’s certainly one of the Diamondbacks’ top options for the late innings.
Injuries have limited his availability the past three seasons. He was limited to 30 appearances in 2025 due to back and shoulder issues. He’s only made 50 total appearances since 2023, which is why he had to settle on a minor league deal.
Why the Diamondbacks Would Gamble on Jonathan Loaisiga
The Diamondbacks struck gold last offseason on a similar signing. Shelby Miller took a minor league pact, made the roster, then became their closer following injuries to A.J. Puk and Justin Martinez. Miller was arguably their best reliever, pitching to a 1.98 ERA and 10 saves. They’re looking for similar results from Loaisiga.
The underlying metrics on Statcast suggest a potential impact reliever if he can stay healthy. He induced chases on 40.6% of the pitches he threw out of the zone and induced whiffs on 26.5% of swings. It didn’t translate to strikeouts, as he produced just an 18.5% strikeout rate. But it produced weak contact, leading to a 50.5% ground ball rate, 35.4% hard-hit rate, and a 6.3% barrel rate.
Even with the lack of strikeouts, the strong quality of contact profile resulted in strong expected metrics. Loaisiga yielded a .237 xBA and a 3.56 xERA in 2025.
The primary concern is that a lat strain ended his 2025 season prematurely. Loaisiga did not pitch in the postseason for the Yankees.
The Arizona Republic‘s Jose Romero spoke to Diamondbacks general manager Mike Hazen about the move. Hazen mentioned the stuff and that Loaisiga is in the mix for the bullpen next spring.
Diamondbacks Still Not Done Fortifying Bullpen
While Loaisiga is a good low-risk, high-reward move, the Diamondbacks can’t realistically depend on him. He was available for a minor league deal for a reason. So they’ll need to make further moves to shore up a bullpen that pitched poorly in 2025.
Arizona Sports radio host John Gambadoro reports that the Diamondbacks are closing in on more bullpen help. They’ll need to target more proven options to try to stabilize the late innings.
The top remaining free agents are Seranthony Dominguez and Michael Kopech. In the trade market, they could make a run at the Pirates‘ Dennis Santana. Santana is in the final year of control with Pittsburgh, so he wouldn’t come at a prohibitive cost.
In the ideal scenario, Loaisiga makes the club and is one of those arms. He fits the profile of what the Diamondbacks are looking for, someone who can step up for the ninth while Puk and Martinez are out. Once those two pitchers return from elbow surgery, then Loaisiga could become a high-leverage setup role.
But with a bullpen that has more questions than answers, they need more pitchers to step up into those roles. Other relievers in the organization that should get consideration next spring include Yilber Diaz, Drey Jameson, and Brandyn Garcia. All three relievers offer the premium stuff necessary to succeed in a back-of-the-bullpen role.
Diamondbacks Take Low-Risk Flier on Former Yankees Flamethrower