
Justin Martinez is a fantasy baseball SP prospect sleeper and minor leaguer to know. Read our MLB prospects outlooks for fantasy baseball rookies and call-ups.
PROSPECT: Justin Martinez, SP, Arizona Diamondbacks
ANALYSIS: When looking at a pitcher that has a 21.60 ERA, dynasty league owners typically check right out. However, the 21-year-old Martinez has really flashed outstanding raw stuff – it’s just a matter of getting it in the zone consistently.
Originally signed in 2018 by the Diamondbacks out of the Dominican Republic, Martinez has been pumping triple-digit fastballs and using a hard slider and a split-finger fastball to offset the heater. The issue has always been control, as he has recorded a 10%+ walk rate at nearly every level.
This past week, Martinez made three appearances, totaling 1 2/3 innings. He walked nine and struck out four in that time, allowing six runs. However, he also generated 11 swings and misses on the week, which is a sign of just how hard it is for hitters to make contact on him when he can locate the ball.
VERDICT: No need to rush for Martinez in any format, but without a clear closer in Arizona, if he can even get his walk rate to his typical career norm, he could be fast-tracked for the role with the Diamondbacks by season end. Watch and pounce if he’s given a shot.
More Fantasy Baseball Analysis

Craig Yoho - Fantasy Baseball Waiver Wire Pickups and Prospect Stashes (Week 4)
BALLER MOVE: Add in 12+ Team Leagues ROSTERED IN: 3% of Leagues ANALYSIS: The Milwaukee Brewers called up their No. 18-ranked prospect, Craig Yoho, ahead of their series opener against the San Francisco Giants on Monday. Yoho has quickly risen up the minor league ranks since being drafted in the eighth round of the 2023 MLB Draft. […]

Nick Kurtz - Fantasy Baseball Waiver Wire Pickups and Prospect Stashes (Week 4)
BALLER MOVE: Add in All Leagues ROSTERED IN: 31% of Leagues ANALYSIS: After weeks of wondering when the Athletics would call up their top prospect, they are finally expected to promote first baseman Nick Kurtz to their major league roster on Monday evening. Kurtz was drafted fourth overall in the 2024 MLB Draft and is currently MLB […]

Logan Henderson - Fantasy Baseball Waiver Wire Pickups and Prospect Stashes (Week 4)
BALLER MOVE: Monitor in 12+ Team Leagues ROSTERED IN: 3% of Leagues ANALYSIS: The Milwaukee Brewers called up their No. 12 prospect, Logan Henderson, earlier this week to give the team another fresh arm. The Brewers are dealing with injuries to Nestor Cortes (elbow), Aaron Civale (hamstring), Brandon Woodruff (shoulder), and Tobias Myers (oblique) early in the […]

Edgar Quero - Fantasy Baseball Waiver Wire Pickups and Prospect Stashes (Week 4)
BALLER MOVE: Add in 15+ Team / Two-Catcher Leagues ROSTERED IN: 1% of Leagues ANALYSIS: The Chicago White Sox called up their No. 6 prospect, Edgar Quero, on Thursday afternoon to make his MLB debut. Quero was acquired by the White Sox at the 2023 trade deadline in the deal that sent both Lucas Giolito and Reynaldo […]

Caleb Durbin - Fantasy Baseball Waiver Wire Pickups and Prospect Stashes (Week 4)
BALLER MOVE: Consider in 12+ Team Leagues ROSTERED IN: 6% of Leagues ANALYSIS: The Milwaukee Brewers have promoted infielder Caleb Durbin, who MLB Pipeline ranked as their No. 21 prospect coming into the season. Durbin will make his MLB debut on Friday night, batting ninth against J.T. Ginn and the Athletics. Before the game, manager Pat […]
Download Our Free News & Alerts Mobile App
Like what you see? Download our updated fantasy baseball app for iPhone and Android with 24x7 player news, injury alerts, sleepers, prospects & more. All free!

Check out RotoBaller's entire fantasy baseball waiver wire pickups and sleepers list, updated daily!