THE APEX TIMES
Susana’s 103.8 tops the AFL, and the Nationals’ No. 4 prospect is flashing “flame-thrower” upside
Jarlin Susana’s velocity surge has him running the Arizona Fall League radar at the same time Washington is trying to manage his workload and tighten his strike zone.
Jarlin Susana is proving why the Nationals have talked about his arm as a future swing factor. In the Arizona Fall League, the 22-year-old right-hander opened his campaign by touching 103.8 mph with a four-seamer, a mark that set the record for the fastest pitch thrown in the AFL since 2015.
The immediate comparison is obvious, at least in style: last week’s MLB postseason coverage included Brewers-Padres action where Jacob Misiorowski repeatedly hit triple digits and set a postseason speed mark at 104.8 mph. Susana is not chasing the same season-specific record here, but his opening-week AFL velocity places him in the same conversation about elite heat.
Washington’s context for Susana is both promising and cautious. Susana entered the year coming off a Grade 1 UCL sprain and returned to pitching on Aug. 11. Across stops from High-A Wilmington through Double-A Harrisburg and Triple-A Rochester, he logged 20 1/3 innings, with the AFL expected to be a chance to increase workload under a controlled plan.
That controlled plan has been part of the org’s messaging. Nationals president of baseball operations Paul Toboni described rehab coordinator Dan Mahoney telling Susana to stay in a specific velocity window as he got loose, emphasizing not ramping too quickly, and Toboni said the exchange left Susana motivated to keep working within the guidance.
At Triple-A, Susana’s radar gun gains were measurable. He averaged 99.9 mph on 39 fastballs, posting the highest average velocity among Triple-A pitchers who threw as many as he did. Even with that pace, the tradeoff remains command: his Minor League walk rate is 4.8 against a 13.0 strikeout rate.
The speed-into-strike-zone equation continues to be the key development task. In his first two AFL games, Susana pitched to a 1.59 ERA while posting a 3.2 walk rate and a 12.7 strikeout rate over 5 2/3 innings, numbers that suggest he can miss bats and hold runs down, but also that walks are still a stat worth tracking as the workload builds.
Why It Matters
- Velocity is only one part of the transition from prospect to impact arm, and Susana’s early AFL results show the Nationals can get plus heat without instant run prevention falling apart.
- Because Washington’s development plan includes careful workload and pitch-speed management after his UCL sprain, the AFL is a stress test of durability and progression rather than a sprint for max innings.
- The command gap matters for how quickly Susana can move up, since his Minor League walk rate indicates he still needs to fill the zone more consistently.
- If the Nationals can pair his fastball run with improved control, he becomes a more direct fit for high-leverage bullpen and rotation needs later on.
Sources
Key Facts
- Jarlin Susana is the Nationals’ No. 4 prospect and ranked No. 66 overall in MLB.
- In the Arizona Fall League, Susana threw a 103.8 mph four-seamer and set the AFL record for fastest pitch since 2015.
- Susana returned to pitching on Aug. 11 after sustaining a Grade 1 UCL sprain the previous year.
- Across High-A Wilmington, Double-A Harrisburg, and Triple-A Rochester, he threw 20 1/3 innings this season.
- At Triple-A Rochester, Susana averaged 99.9 mph on 39 fastballs and recorded the highest average velocity among Triple-A pitchers who threw at least as many pitches.
- Susana’s first two AFL games included a 1.59 ERA, a 3.2 walk rate, and a 12.7 strikeout rate over 5 2/3 innings.