Scouting Report

Scouting grades: Fastball: 55 | Curveball: 50 | Slider: 50 | Changeup: 50 | Control: 50 | Overall: 50

The top player from Mexico in the class, Martinez is large and tall with a very projectable body and tons of flexibility.

He projects to be a starter if he can maintain his consistency in the strike zone and improve on his secondary pitches. For now, his fastball hovers in the 89-91 mph range and his velocity is expected to increase as he matures and adds strength. There is already some sink in his fastball, and he creates some deception with his arm angle. He also has a high arm slot.

He shows signs of fade to his changeup and a sharp bite to his curveball, but both are works in progress. He already shows good command of the strike zone and has an idea of how to attack hitters. He has experience playing in the showcase circuit in the United States.

Martinez trains with Showtime Top Velocity. The Mariners are among the teams who have shown strong interest in him.

Scouting grades: Fastball: 55 | Slider: 55 | Changeup: 50 | Control: 40 | Overall: 40

A Top 50 international prospect in 2023, Martinez signed with the Mariners for $600,000 when that signing period opened in January. He pitched well, albeit with poor control in his first two stops as a pro, the Dominican Summer and Arizona Complex Leagues. His transition to full-season ball was rough, plagued by poor command in and out of the zone. His July was much better and then he was sent to the Pirates in return for reliever Caleb Ferguson.

Martinez is a big, physical 6-foot-4 right-hander with a huge fastball. His heater sat around 95 mph in 2025, touching 97, and he can throw it with decent sink to get ground-ball outs. His mid-80s slider has the chance to be an out pitch, but it was very inconsistent and the Pirates sent Martinez to pitch design camp to help turn it into more of a bat-misser. He’ll flash a good upper-80s changeup but didn’t throw it a lot last year and really struggled to land it in the zone.

That’s the biggest thing standing in Martinez’s way. Per Synergy, he threw just 58 percent strikes overall in 2025, leading to a 5.8 BB per nine rate, and when he was in the zone, he got too much of the plate, leading to getting hit. He’ll pitch at age 20 for all of 2026, so there’s time for him to work with the Pirates to turn this upside play into a big league contributor.

Scouting grades: Fastball: 55 | Slider: 55 | Changeup: 50 | Control: 40 | Overall: 40

Martinez was one of just seven pitchers on MLB Pipeline’s Top 50 International Prospects list when the 2023 signing period opened. While the Mariners may have made more noise in signing some elite-level hitters on the international market, they weren’t afraid to go after Martinez, whom they signed for $600,000 in January 2023, adding to a class headlined by Felnin Celesten. In Martinez's two stops heading into 2025, the Dominican Summer League and the Arizona Complex League, he showed his raw stuff can get hitters out -- when he knows where it’s going. He struggled to find consistency for much of his first taste of full-season ball this year, but was having his best month in July when he was sent to the Pirates in the Caleb Ferguson trade.

There are still plenty of reasons to be high on Martinez: his athleticism, his size -- he’s 6-foot-4 -- and his power stuff. The teenaged right-hander has seen velocity gains in the early stages of his career, and his fastball now sits around 94-95 mph and touches the upper 90s, and he can really sink it to get ground-ball outs. While his changeup was his better secondary pitch in the DSL, his slider has now caught up and surpassed it.

In the DSL, Martinez did a nice job of being in and around the strike zone, even with his upticks in velocity. He didn’t replicate that when he came stateside and his command issues after walking seven batters per nine in the ACL -- and 5.5 per nine in the California League at the time of the trade -- have raised some reliever-risk flags. He's pitched all of the 2025 season at age 19, so there’s no reason to restrict him just yet, but he’ll need to seriously refine his command to remain in a rotation.

Scouting grades: Fastball: 55 | Slider: 45 | Changeup: 50 | Control: 50 | Overall: 40

Martinez ranked No. 42 among MLB Pipeline’s international prospects when he signed with Seattle for $600,000 out of Mexico in 2023. He blossomed onto many teams’ radars after playing in the showcase circuit in the U.S., with long-term starter potential -- particularly after a stellar debut season in the Dominican Summer League, where he carried a 1.72 ERA, 0.79 WHIP and 30.7 percent strikeout rate in 47 innings.

At just 17 years old during his debut, while leveraging a huge 6-foot-4 frame, Martinez’s fastball made a huge velocity jump in just one year, from sitting in the 89-90 mph range all the way up to 93-94, even touching 97 thanks to a combination of getting onto the Mariners’ Dominican campus and making a small mechanical tweak. Through it all, Martinez retained his plus strike-throwing ability, which can often be sacrificed among youngsters growing into velocity. Among his secondaries, the changeup was better than the slider in the DSL.

The Mariners haven’t had nearly as much success with pitchers on the international market in the Jerry Dipoto era -- those have mostly come via the Draft -- but there’s more than a strong chance that Martinez could blossom into one of the organization’s best in the coming years, with the ceiling of being a mid-to-high-rotation starter.

Scouting grades: Fastball: 55 | Slider: 50 | Changeup: 45 | Control: 50 | Overall: 40

Martinez signed with the Mariners for $600,000 out of Mexico in January and sits in the Top 50 on MLB Pipeline’s list of international prospects. The 17-year-old, who has experience playing on the showcase circuit in the United States, projects to be a starter if he can maintain his consistency in the strike zone and improve on his secondary pitches. 

Seattle assigned Martinez to the Rookie-level Dominican Summer League to begin his professional career. Martinez’s fastball sits in the 90-92 mph range but can touch 94. There’s an expectation the velocity will increase as he matures and adds strength. There is already some sink in his fastball, and he creates some deception with his arm angle. He also has a high arm slot.

He shows signs of fade to his changeup, but the pitch is still a work in progress and definitely third on his depth chart. Martinez’s slider is a slurvy pitch thrown in the 79-81 mph range, but he went into the signing period with solid command of the strike zone and has an idea of how to attack hitters. His slider is already an out pitch and the best swing-and-miss offering in his repertoire.

Awards

Baseball America Rookie All-Star

Year	Team
2023

DSL Mid-Season All-Star

Year	Team
2023

DSL Pitcher of the Week

Week	Team
07/23/2023
06/18/2023

Transactions

Team	Date	Transaction
	03/05/2026	RHP Jeter Martinez assigned to Pittsburgh Pirates Prospects.
	08/26/2025	RHP Jeter Martinez assigned to Bradenton Marauders from Greensboro Grasshoppers.
	07/30/2025	Pittsburgh Pirates traded LHP Caleb Ferguson to Seattle Mariners for RHP Jeter Martinez.
	07/30/2025	RHP Jeter Martinez assigned to Greensboro Grasshoppers.
	04/02/2025	RHP Jeter Martinez assigned to Modesto Nuts from ACL Mariners.
	03/06/2025	activated RHP Jeter Martinez.
	05/03/2024	RHP Jeter Martinez assigned to ACL Mariners from DSL Mariners.
	03/07/2024	Seattle Mariners Prospects activated RHP Jeter Martinez.
	07/29/2023	DSL AL All-Stars activated RHP Jeter Martinez.
	06/04/2023	RHP Jeter Martinez assigned to DSL Mariners.
	01/15/2023	Seattle Mariners signed free agent RHP Jeter Martinez to a minor league contract.