Keyner Martinez

Organization Prospect Rankings

• 
  Ranked San Francisco Giants #6 prospect in 2026
  BA Grade/Risk: 55/High
  
  Adjusted Grade: 40
  
  Track Record: Martinez signed out of Venezuela as an 18-year-old in July 2023 and didn’t make his pro debut until the following year in the Arizona Complex League. In his first turn in the desert, Martinez looked like a pitcher with little more than a live arm. A year later, his stuff ticked up, his arsenal widened and he surged up the system’s pitching hierarchy. After a dominant run in the ACL, Martinez finished the year in Low-A, where he helped San Jose claim the California League crown.
  
  Scouting Report: At the very least, Martinez will likely be able to bully hitters with his fastball and slider. The former sits in the mid 90s and peaked at 98 with solid carrying life. He pounded the zone with the pitch, collecting strikes at a 70% clip and misses at a rate of 25.5%. Martinez backs it with a sweeping slider that went through a dramatic transformation from the version he used in 2024. The Giants suggested a grip switch during a bullpen session, and Martinez took to the change immediately. Now, the breaking ball is an out pitch and an easy plus offering. He introduced his changeup in the middle of the 2025 season and scouts universally said that he showed improved feel for the pitch as the year went along. The righthander’s strike-throwing dipped a bit after moving to Low-A, so he’ll have to work a bit to improve his control against more advanced hitters. Martinez’s physicality should help him hold up to a starter’s workload, though some scouts believe an upright finish and a lack of extension in his delivery could lead him to the bullpen.
  
  The Future: Martinez should return to Low-A in 2026. If he can hold up to a longer workload and bring his changeup forward a couple of ticks, he has a ceiling of a midrotation starter.
  
  Scouting Grades Fastball: 60 | Sweeper: 60 | Changeup: 45 | Control: 55.