Sep 16, 2025; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher John Curtiss against the San Francisco Giants at Chase Field. Mandatory Credit: Mark J. Rebilas-Imagn Images Mark J. Rebilas-Imagn Images

D-backs Reunite with Reliever to Bolster Bullpen Depth

Originally posted on Arizona Diamondbacks on SI
By Alex D'Agostino | Last updated Dec 18, 2025 3:07 PM ET

According to their transaction log page , the Arizona Diamondbacks have reunited with one of their 2025 relief arms, signing right-hander John Curtiss to a minor league deal, assumedly with an invite to big league Spring Training.

Curtiss was an under-the-radar asset for the D-backs in 2025, putting forward a solid, if not eye-popping season in a year that claimed many of Arizona's top-end leverage arms.

Arizona Diamondbacks Re-Sign John Curtiss

Joe Camporeale-Imagn Images

Curtiss, a 32-year-old journeyman reliever, pitched to a sturdy-enough 3.93 ERA and 4.01 FIP over the course of 30 appearances (36.2 total innings). He went 3-2 and recorded his first save in four years. While certainly not a top-tier bullpen weapon, Curtiss provided valuable innings for Arizona.

The right-hander had signed a minor league deal with the D-backs in 2025 back in February, before the season began. He was eventually called up on June 28, and with the injuries continuing to pile up on Arizona's bullpen, remained with the big league club for the duration of the season.

Curtiss' ability to provide length, delivering more than one inning on numerous occasions, made him a valuable piece of a bullpen that desperately needed quality innings coverage. Having him return to compete for a similar middle relief role can only stand to benefit Arizona.

"I'm just grateful to still be in the league," Curtiss said to D-backs.TV's Todd Walsh after recording an extra-inning win against the Minnesota Twins (a former club of his) on September 13.

"The likelihood of me still being here on September 13th of 2025 did not seem very high when I got designated for assignment in December or January of 2019 at this point, so I'm just happy to still be here and still be competing."

Curtiss seems likely to find a role back on the MLB roster again, barring major external additions this offseason. Even so, there could be a spot for him in less high-leverage situations. Though he handled the back end assignment well in 2025, the D-backs would do well to land multiple leverage arms in the coming months.

Arizona's bullpen was one of the many sore spots on the roster in 2025. The very fact that Arizona had to turn to so many journeyman arms like Curtiss is a testament to how brutal navigating the relief space was this past season.

But Curtiss stood out as more than just a cast-off. He truly pitched well for the D-backs under less-than-ideal circumstances, and seems likely to bring at least some value back in his return.