Jeter Martinez Joins Pirates As Next Power Arm Prospect

The Pittsburgh Pirates added another high-upside arm to their pitching pipeline with the acquisition of Jeter Martinez.

The 19-year-old right-hander came over from the Seattle Mariners on July 30 in exchange for left-handed reliever Caleb Ferguson, and while Martinez is still a work in progress, the tools are evident. At 6-foot-4, Martinez brings a prototypical frame and developing arsenal that has already flashed promise across two pro seasons.

Martinez stands 6-foot-4 — the kind of frame teams dream on — and his stuff is starting to catch up. He broke out in the Dominican Summer League in 2023 and signed with Seattle as one of the top arms in that year’s international class, earning a $600,000 bonus out of Mexico.

His fastball, once clocked in the high 70s, now sits comfortably in the mid-90s and can reach the upper 90s according to MLB.com. He has shown an ability to generate both whiffs and grounders with the heater, which pairs well with a cutter, an improving slider and a changeup that was once considered his top secondary.

Martinez’s first stateside action in the Arizona Complex League and California League revealed just how much polish remains. Command has been his biggest hurdle.

He walked seven per nine in the ACL and 5.5 per nine after moving up, though his strikeout numbers remained encouraging. That blend of swing-and-miss stuff and inconsistent control has led some evaluators to raise potential bullpen projections. But at just 19, there is still ample time for him to round into form.

Martinez has also dabbled with a curveball, attempting to deepen an already intriguing mix. His long, smooth arm action suggests it could eventually become a viable piece of his repertoire if the control comes along.

For now, he remains a developmental project. But the Pirates, who continue to stockpile young arms with upside, clearly believe in his ceiling. Martinez joins a growing stable of promising right-handed pitching that includes Bubba Chandler, Thomas Harrington and Michael Kennedy — giving Pittsburgh yet another promising arm to develop in a system already regarded as a pitching factory.

More MLB: Top Pirates Prospect Lost for Season With Shoulder Injury