How Electric Flamethrower Emerged for the Diamondbacks

There's potential here, but some improvement is necessary.

Aug 24, 2025; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Juan Morillo against the Cincinnati Reds at Chase Field. Mandatory Credit: Mark J. Rebilas-Imagn Images | Mark J. Rebilas-Imagn Images

The Arizona Diamondbacks' 2025 season was one that will stand out, at least in recent history, as one of the more brutal, unpredictable seasons this franchise has had to endure.

Despite high expectations, the D-backs fell to an 80-82 record, losing key player after key player to injury and struggling with severe underperformance along the way.

With so many injuries — particularly in the bullpen — Arizona had to turn to a massive number of pitchers to get through 2025. Some emerged as surprise contributors, while others struggled.

One such arm the D-backs discovered was flamethrowing righty Juan Morillo. Morillo was an under-the-radar minor league signing who emerged as a high-octane major league option, but struggled with command and consistency.

He was electric at times, and unstable in other instances, but was still a relatively valuable member of the 2025 D-backs.

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: Juan Morillo

Arizona Diamondbacks pitcher Juan Morillo 2025 statistics | Alex D'Agostino

The Diamondbacks signed Morillo to a minor league deal ahead of the 2025 season, after catcher Jose Herrera — who had worked with Morillo in winter ball — pointed him out to Arizona's front office.

The D-backs took a chance on the 26-year-old righty, in part due to his upper-90s and sometimes triple-digit fastball. He'd been with the Los Angeles Dodgers' organization since signing as a 16-year-old nearly a decade prior.

Related Content: How the Diamondbacks Uncovered This Hidden Bullpen Gem

Morillo was called up to the majors on April 19, and allowed just two unearned runs in his first five appearances. The electricity was there, but he then struggled to a 7.94 ERA in the month of May.

Morillo had an up-and-down 2025, both in terms of results and with regard to his roster status. He traveled to and from the D-backs' minor leagues multiple times, and posted some excellent and some poor results.

He recorded his first career save on August 12 against the Texas Rangers, but then was responsible for a failed-comeback loss against the Brewers not long after. In general, Morillo looked like a major leaguer, but struggled with consistency, both of results and command.

Juan Morillo: 2026 Outlook

Morillo will absolutely have an opportunity to take a major league role in 2026, but he'll need to work on his walk issue. As is often the case with high-velocity throwers (and Morillo throughout his professional career), a significant walk output was present. The righty allowed 5.24 free passes per nine innings in the majors and often had difficulty finding the zone.

Morillo pitched to a 2.57 ERA in 21 appearances with Triple-A Reno — in a very offense-heavy environment. He also posted a 3.63 FIP in the majors, with 36 strikeouts in 34.1 innings. It's clear he's capable of getting outs, even at the highest level, but he'll need to significantly reduce the walks and post more consistent results to become a full-time contributor to Arizona's bullpen.