Player Development Miami Marlins, Dominican Summer League · 2025
DSL Returning Hitters Analysis
The hitting department could see development happening. Did the year-over-year numbers back up what the coaches were seeing on the field?
The Headline: From 2024 to 2025, Marlins DSL returning hitters posted the #1 hard-hit rate improvement and #2 chase rate improvement among all 25 qualifying MLB organizations, and all 14 qualifying hitters improved in at least one development pillar.
Project Overview
Purpose
- Evaluate year-over-year player development effectiveness in the Miami Marlins DR Academy by analyzing key pillar improvements of returning hitters from 2024 to 2025
Objectives
- Measure individual player improvements across key pillar metrics
- Rank DSL Miami Marlins hitters against league-wide DSL returning-hitter performance
- Identify development successes and areas for continued focus
Parameters and Constraints
Player Criteria
DSL returning hitters with 50+ PA in both 2024 and 2025 (14 DSL Miami Marlins players qualified)
Comparison Group
252 total DSL returning hitters · organizations with 5+ qualifying players
Time Period
2024 and 2025 DSL regular seasons
Key Methodology
- Improvement rankings calculated as percentile rankings among all 252 DSL returning hitters
- Year-over-year changes measured as percentage-point differences between seasons
- League context provided for all individual player improvements
A note on the numbers: chase, contact, and exit-velocity metrics are derived from league tracking data, so they’re presented here as rankings and percentiles only, with raw values withheld. Walk and strikeout rates are public record and shown in full.
Organizational Results
| Metric | Org Improvement Rank (of 25) |
|---|---|
| Hard-Hit Rate (95+ mph EV) | #1 |
| Chase Rate | #2 |
| In-Zone Contact | #4 |
| Strikeout Rate | #13 |
| Walk Rate | #14 |
The organization’s two biggest gains, contact quality and swing decisions, are exactly where it separated from the league.
Individual Results
- All 14 hitters improved in at least one pillar, averaging improvements in 5+ metrics each
- Two 100th-percentile improvements among all 252 DSL returners: Jose Castro posted the league’s largest in-zone contact gain, and Adrian Bello its largest chase-rate cut
- Jesus Abreu and Adrian Bello each improved in seven categories
- 5 of 14 hitters landed in the top 10% of league-wide improvement rankings
The public stat line shows what that development looked like:
| Hitter | Public Stat | Change | League Percentile |
|---|---|---|---|
| Adrian Bello | K% | −16.8 pts | 99th |
| Adrian Bello | BB% | +8.1 pts | 92nd |
| Almen Tolentino | K% | −13.7 pts | 95th |
| Jayden Felicia | BB% | +10.5 pts | 98th |
How a Team Uses This
The hitting department came in with a specific question. They could visually see the development happening, but did the year-over-year numbers actually back up what the coaches were seeing on the field? This analysis put numbers behind it, and the answer was yes: the organization’s two biggest gains were hard contact and chase discipline, two of the clearest signals of hitter development at this level.
The league-wide benchmark was just as important as the year-over-year change. Comparing every Marlins hitter against the full pool of 252 DSL returning hitters separated real development from league-wide trends, so a top-ranked improvement meant the program outpaced the other 24 organizations rather than riding a rising tide. The framework also flagged where to focus next (walk rate held steady rather than gaining), and I built it to be repeatable, so the same analysis could be run for any future season or extended to pitchers.