Diamondbacks' Top Prospects for 2026

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October 5, 2025

The Arizona Diamondbacks‘ 2025 season proved to be a transitional one. Roster turnover, trade deadline trades and injuries exposed several obvious gaps at the end of the year. As the team prepares for 2026, it’s time to shift the focus inward. Which of the Diamondbacks’ top prospects for 2026 are ready to make the leap into the big leagues to fill these holes? In this article, we’ll identify five Diamondbacks 2026 prospects that have a real shot to get major league playing time in 2026. The analysis took into account recent performance, position fit relative to roster needs and trajectory. It’s not realistic to think that a Single-A player will make the MLB roster in 2026. A few may challenge for a spot in Spring Training. But a few others could debut after the season has started. Each prospect has his upside and some risk that makes him worth watching.

1. Adrian Del Castillo – Catcher

Adrian Del Castillo (26) – Jose Herrera, the backup catcher, has elected to try free agency. Castillo had 166 at-bats in 2025. Adrian Del Castillo had 120 at-bats, but mostly as a DH. He started only 4 games during the year, but at 26 years old and with a stat line of .288/.386/.559/.945 in Triple-A in 2025, he’s ready to make the jump and serve as the backup to Gabriel Moreno. He has had some injuries, and his defense needs some improvement. But he’ll get a lot of reps in Spring Training and his bat will help solidify his spot on the big-league roster, and he is definitely the Diamondbacks’ top prospect for 2026.

2. Jordan Lawlar – Shortstop, Second Base, Third Base

Jordan Lawlar (23) – He’s been on this list before. In 2023, he got 31 at-bats with the Diamondbacks. In 2025, he got another chance with 66 at-bats. He hit .129 in 2023 and .182 this past season. He did hit .313 in Triple-A last year, showing he does have the skill, but he never seems to show it at the major league level. His versatility could help, but he’s a better middle infielder than third baseman, which is a problem with Geraldo Perdomo and Ketel Marte holding down those spots. He’ll only be 24 years old in 2026, so he still has time. He’ll most likely be a utility player at this point if he makes the team, but that’s still questionable at this time.

3. Cristian Mena – Right-Handed Pitcher

Cristian Mena (22) – Cristian pitched two innings for the Diamondbacks in 2024 and 6 2/3 innings in 2025. It’s a small sample size, but he did have a 1.45 ERA in 2025. He also had a 0.900 WHIP. That doesn’t exactly fit his recent minor league stats, where he hasn’t had an ERA under 4.61 since 2022. His WHIP at Triple-A in 2025 was decent at 1.388. His K/9 is almost always over 10.0. Maybe the extra pressure of a big-league game is what he needed to focus. If he can do that again in Spring Training, he’s got a small shot at making the Opening Day roster. He would be the youngest player on the big-league roster, at age 23. Most likely, he’s an in-season call-up if he can keep the WHIP below 1.300.

4. Hayden Durke – Right-Handed Pitcher

Hayden Durke (23) – Possibly the pitcher with the most upside in this group and maybe the entire organization. Rocketing up the organization after being drafted in 2023, he can be unhittable at times. At the Single-A level in 2024, he pitched 49 innings, giving up only 24 hits. He also had 69 strikeouts with a 2.33 ERA. Then to Double-A in 2025, he pitched 20 1/3 innings, allowing only three hits. You read that right. Three hits in 20 1/3 innings. He had 36 strikeouts, a 0.89 ERA and 0.689 WHIP. He quickly moved to Double-A and kept it going. 11 2/3 innings pitched, four hits and 18 strikeouts. His ERA was 2.31 while his WHIP was 0.857. He did get hit around a little in 17 innings after being moved up to Triple-A last year, but that seems to be the anomaly. Anywhere he’s had some decent innings, he’s been amazing. His fastball averages 95.3 mph. If he dominates like that in Spring Training, they can’t help but keep him. He’s almost a guarantee to hit the Majors by 2027, after one full year in Triple-A.

5. Yilber Diaz – Relief Pitcher

Yilber Diaz (25) – This young man can bring the heat. His fastball can hit 99 mph, with his average being about 96 mph. He’s a strikeout pitcher but has shown terrible control– think early Randy Johnson. In 2025, he pitched 57 innings and had 70 strikeouts in three levels of minor league ball. But he also had a whopping 73 walks! In his lone appearance for the Diamondbacks in 2025, he threw three innings of relief. He gave up four hits and three walks, striking out one. If someone can get him to hit the strike zone with all his pitches, he’s definitely a big-league arm and would be fun to watch. Spring Training will be the key to where he ends up starting the season.

Looking Ahead

If 2025 taught us anything, it’s that internal reinforcements will be critical in 2026. The Diamondbacks are not going to break the bank in the free agent market. The five Diamondbacks’ top prospects for 2026 mentioned represent the best chances at filling needs from within. Keep an eye on these guys during Spring Training, as they are going to be the Diamondbacks’ top prospects for 2026.