Arizona Diamondbacks’ 2026 Non-Roster Invitees Part 2: Hidden Gems Ready to Shake Up the Season

Right-handed pitchers on the rise – that’s what we’ve got lined up for this spring training, and trust me, it’s quite the parade. Fourteen of these NRIs are shaking things up, promising plenty of intrigue over multiple deep dives. This batch? It’s heavy on bullpen hopefuls, the kind who might not storm the mound immediately but could prove critical down the line. Among them are some fascinating stories – take Isaiah Campbell, the first Portugal-born player to make it to the majors in nearly a century and a half, or John Curtiss, whose 2025 stint with the Diamondbacks showed he’s far from done. From seasoned veterans bouncing back to promising youngsters still finding their footing, this group offers a mosaic of potential and perseverance that’s hard to overlook. Strap in, because these arms might just redefine the depth charts sooner than you think. LEARN MORE

We move on to the slew of right-handed pitchers present as NRIs to spring training this year. There are no fewer than fourteen, so this will take us a few installments! A lot of relief arms: all five in this edition are potential help for the bullpen, though perhaps not as soon as this season.

Isaiah Campbell (49)

Campbell is the first man born in Portugal to reach the majors in almost a hundred and fifty years, since the Madeira-born Frank Thompson in 1875. Isaiah was born when his father was serving there in the Air Force. He debuted in 2023 with the Mariners, and had a fine rookie campaign, posting a 2.83 ERA across 27 relief appearances. He has struggled since, missing much of 2024 with elbow inflammation. Last year, he pitched mostly for Triple-A Worcester, and had a 3.90 ERA for them, but couldn’t find success in the big leagues with the Red Sox. He’s not a terrible depth piece and, with just over a year’s service time, comes with a lot of team control.

Gerardo Carrillo (68)

A career minor-leaguer, Carrillo has bounced around since 2017, and only made two appearances above Double-A in that time. Now aged 27, he has seen time with the Dodgers, Nationals and Rangers organizations, before signing a minor-league deal for the D-backs. He actually appeared in the Arizona Fall League, back in 2019. Last year, he had a 3.59 ERA for Double-A El Paso, and over the winter had a 2.19 ERA for Jalisco in the Mexican League, though his K:BB ratio was an unimpressive 4:4 over 12.1 innings. He’s probably most famous for being part of the Max Scherzer + Trea Turner deal between Los Angeles and Washington in July 2021.

John Curtiss (46)

This name, however, should be familiar, because Curtiss – with the extra S – appeared thirty times out of the Arizona bullpen in 2025 (pictured, top). He didn’t do at all badly, getting a 3.93 ERA and 4.01 FIP. He got a decent 4.80 rating in our season review, but was outrighted off the 40-man roster at year end, and elected to become a free agent. However, he re-signed for the Diamondbacks on December 16, and the experience he picked up – Curtiss even notched a save – will stand him in good stead. He walked just five batters in 36.2 innings, and John should definitely be considered a contender for one of the open spots at the back of the 2026 bullpen.

Shawn Dubin (65)

Like Campbell, Dubin comes with major-league experience, having appeared 64 times for Baltimore and Houston, since making his MLB debut in June 2023. Last year, he started with the Astros, but was selected off waivers by the Orioles in August. All told, he had a 5.08 ERA over 33.2 innings, with a 28:11 K:BB. It’s possible health was an issue, as he was much better (1.33 ERA in 20.1 IP) before a forearm strain sent him to the IL for two months in June. Fun fact: Dubin originally intended to play soccer at college, and dropped out to work at Lowe’s. A friend convinced him to try out for the baseball team at Erie Community College… and here we are.

Hayden Durke (53)

A 13th-round pick in 2023, Durke rocketed through the system last year, with stops at three levels. He started at High-A Hillsboro, where a 13.2 inning scoreless streak with 22 strikeouts led to him moving up to Double-A Amarillo. Despite its well-known reputation as a launching pad, Durke held his own, with a 2.31 ERA and 18:6 K:BB across 11.2 frames. He was then sent to Reno and… [loud buzzing sounds of static] Yeah, it didn’t quite go as well there, his control evaporating to the tune of more than a walk per inning, and a 9.53 ERA in 17 games. Still, he’s only 23, so has time to figure it out.