Diamondbacks Top Prospects #29: RHP Justin Martinez

Martinez is a hard-throwing reliever that could make an impact in the D-backs bullpen sooner rather than later.

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Name: Justin Martinez

Age: 21

Position: Relief Pitcher

Acquired: International Free Agent, March 2018, $50K signing bonus

Tools: Fastball 70, Slider 45, Changeup 45, Command 30, Overall 40

Martinez has a very electric fastball, in the 97-100 MPH range with good carry at the top of the strike zone thanks to a spin rate around 2500 RPM. (MLB average is 2276) His fastball movement is almost purely vertical, which is the type of profile that the Diamondbacks covet. When located at the top of the zone, he blows away hitters with velocity. His slider and changeup don't have a great movement profile, but enough horizontal movement to be complementary to his fastball. Command is a big concern, as he's still more of a thrower than a pitcher at this stage of his career.

ETA: 2023

Risk: High

Top 30 List

2022 Overview

Martinez underwent Tommy John surgery in 2021, returning in July with High-A Hillsboro after a couple rehab outings at the complex. He appeared in 25 games, going 3-3 with a 3.32 ERA and a 62/22 strikeout to walk ratio in 38 innings between High-A, Double-A, and Triple-A. After being moved up the system quickly, Martinez got assigned to the Arizona Fall League after Reno's bid for a Triple-A Championship fell short. It's no surprise they've moved him quickly, as he is eligible for the Rule 5 Draft for the first time this off-season.

2023 Outlook 

Given his high octane arm and how quickly the D-backs moved Martinez up the system, it's a safe bet that he'll be added to the 40-man roster. That will put him in the mix for a potential bullpen spot next spring, with an assignment to Triple-A Reno should he not win one. Martinez posted an impressive strikeout rate of 36.7% strikeout rate in his Age 20 season, so if he can throw strikes he'll be in the big league bullpen sooner rather than later. The issue is a 13.0% walk rate, which can be problematic if not corrected. He'll likely see at least 20 appearances with the big league bullpen, regardless of where the D-backs are in the standings.

MLB Projection

Given the fact that Martinez already has had one major arm injury to go with swing-and-miss stuff, the bullpen is the best place for him to contribute both in the short and long term. His role will depend on how consistently he throws strikes, ranging from being an up-and-down arm the next couple seasons with the upside of a potential closer. With the need to add velocity and strikeouts to one of the worst big league bullpens, they may have a diamond in the rough with Martinez.