Journeyman Reliever was Surprise Contributor for D-backs

The Diamondbacks got quality innings out of this reliever.

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

The Arizona Diamondbacks' 2025 season was certainly not for the faint of heart. Despite the high expectations of a competitive, playoff-contending team, the D-backs sputtered to the tune of an 80-82 record, missing the Postseason for the third straight year.

Injuries played a massive role in the overall disappointment of 2025. In particular, Arizona's pitching staff (especially the bullpen) endured a high volume of injuries to critical arms, which forced a number of young, unproven arms and veteran journeymen into more prominent roles.

One such journeyman was right-handed reliever John Curtiss, who had a relatively successful 2025 season, despite the circumstances. Curtiss became one of the more reliable arms in a battered, underperforming group of relievers as the season grew old.

As Arizona Diamondbacks On SI continues to break down the individual seasons of every player that contributed to the 2025 D-backs roster, the below article will be updated with the proper links to every season review as they are published.

Related Content: Breaking Down Every Diamondbacks Player's 2025 Season

Arizona Diamondbacks 2025 Player Review: John Curtiss

John Curtiss 2025 and career statistics | Alex D'Agostino

Curtiss signed a minor league deal with the D-backs late in the offseason, inviting the veteran righty to Spring Training to compete for a role.

Curtiss did not initially make it into Arizona's big league bullpen, and he landed on the IL not long following. He was eventually called up to the majors on June 28 to fill some innings. The D-backs needed coverage above all else as arm after arm went down with injury.

Though he did fall victim to a handful of blowup outings in July (with a 7.27 monthly ERA in seven appearances) he began to deliver quality results in August and beyond. He pitched to a 2.12 ERA in 17 August innings, then saw his September ERA inflated by one four-run appearance, allowing only one run in his nine other frames to end 2025.

Curtiss elected free agency at season's end, but recently re-signed on another minor league deal with the D-backs.

Related Content: D-backs Reunite with Reliever to Bolster Bullpen Depth

John Curtiss: 2026 Outlook

Curtiss will likely compete for a role again this Spring, though he's already proven his ability to get outs at the major league level.

His ability to pitch multiple innings adds some value, and he could be a quality middle relief option for Arizona, though the club is still in dire need of leverage relief reinforcements as they await the return of Justin Martinez and A.J. Puk.