Diamondbacks' Top-10 Pitching Prospect Makes Electric Season Debut

It took him a while to get into a minor league game this year, but this was impressive.

Arizona Diamondbacks pitching prospect David Hagaman at Salt River Fields in Scottsdale, Arizona. | Jack Sommers.

One of the more intriguing young arms in the Arizona Diamondbacks' system made his season debut for the High-A Hillsboro Hops on Wednesday night, and put on quite the show in a truncated start.

23-year-old right-handed starting pitcher David Hagaman, who currently ranks No. 8 among D-backs prospects per MLB Pipeline (and No. 2 among Arizona's pitching prospects), made his first start of 2026 for one of the D-backs' affiliate clubs.

Over the course of just two innings, Hagaman did not allow a run or a base hit. He issued two walks, but managed to punch out an impressive five batters — retiring all but three of the eight batters he faced via the strikeout.

But, why was Hagaman's start so delayed?

Diamondbacks' David Hagaman makes return to minor league action

Apr 4, 2025; Washington, District of Columbia, USA; A detailed view of an Arizona Diamondbacks hat at the game between the Washington Nationals and the Arizona Diamondbacks at Nationals Park. Mandatory Credit: Reggie Hildred-Imagn Images | Reggie Hildred-Imagn Images

Hagaman was not given a traditional injury designation following his stint in the Arizona Fall League come season's end in 2025.

But he did not participate in big league spring training, and was not assigned to a minor league affiliate until Tuesday, when he was assigned to High-A Hillsboro for the second straight season.

It's possible that Hagaman had been dealing with general fatigue or soreness that was not severe enough to warrant a stint on the injured list, but that was never reported officially. He was sent to extended spring training on April 9 in order to build up toward minor league action once again.

Hagaman was part of the return of the Merrill Kelly trade. He was one of three starting pitching prospects sent over from the Rangers at the 2025 Deadline, alongside twin left-handers Mitch Bratt and Kohl Drake.

Despite being the furthest away from a potential major league debut, the right-handed Hagaman may end up having the highest ceiling of the three.

He pitched to a stellar 3.15 ERA over the course of his five starts for Hillsboro post-trade. During that process, he struck out an immense 27 batters in just 20 High-A innings. For the full season, he held a 2.98 ERA with 55 strikeouts in 42.1 innings across three different teams. The swing-and-miss factor is very strong with the young righty.

Though Hagaman had some mixed results during the fall league, he punched out 14 batters in 12 innings during that section of the offseason, as well.

As it stands, Hagaman is far away from a major league debut, but he may have the most sustainable game of the three former Rangers prospects in the deal that brought him to Arizona. A swift promotion to Double-A Amarillo after Hagaman ramps up fully would not be a shock to witness, whatsoever.