Jostin Florentino

Organization Prospect Rankings

• 
  Ranked Chicago Cubs #15 prospect in 2026
  BA Grade/Risk: 50/Extreme
  
  Adjusted Grade: 30
  
  Track Record: The younger brother of Pirates prospect Antwone Kelly, Jaitoine threw mostly in the upper 80s with a raw delivery and underdeveloped secondary stuff when the Diamondbacks started scouting him in 2023. Liking his size and the way he moved—and the fact that his older brother threw significantly harder despite having a smaller, stockier build—the Diamondbacks signed Kelly for $70,000 on what was a deep projection play. A couple years later, it is looking like a sharp investment. Kelly’s fastball made a big jump in 2025 and he looks like he could have the makings of a future starting pitcher.
  
  Scouting Report: After averaging 88.3 mph and topping out around 91-92 mph in 2024, Kelly’s fastball averaged 92.6 mph and touched 95-96 in 2025. He averaged 17.2 inches of carry and has been up to 7 feet of extension. His best secondary is a kick changeup with good fade that can resemble a splitter. He has a slow, sweepy curveball that grades as below-average; he might need to add a harder, shorter breaking ball that would pair better with his fastball. He has an above-average delivery and arm action and made huge strides in his strike-throwing. He will need to continue to work on his body to maintain athleticism.
  
  The Future: Kelly has a long way to go but has significant upside given his arm and frame. If it all comes together, he has the potential to be a midrotation starter.
  
  Scouting Grades: Fastball: 60 | Curveball: 45 | Slider: - | Changeup: 55 | Control: 50