Few pitchers illustrate the marriage of data and performance better than Philadelphia Phillies left-hander Jesús Luzardo.
When the left-hander burst onto the MLB scene, scouts marveled at his raw stuff: an electric fastball and a wipeout slider.
Yet through his first few seasons, inconsistency plagued him. In 2021, his ERA ballooned above 6.50, and questions arose about whether he could harness his arsenal into front-line production.
Over the past four seasons he’s rebuilt his delivery transforming from a talented but inconsistent starter into one of the National League’s toughest matchups.
The secret? A deliberate change in his arm angle and release profile.
A recent MLB article details how Luzardo’s 2025 surge stems from a return to a lower, more natural slot after briefly raising it in 2024.
His Rapsodo practice data from 2020-2023 provides a rich prequel to that story, showing exactly how his release points shifted and how those mechanical changes lined up with on-field results.
The Practice Data: Four Seasons of Measured Change
Release Height: From Volatile to Locked-In
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2020 – Heights scattered from ~4.5–6.3 ft, with wide variability (avg. ~5.6 ft). This volatility mirrored his rookie-year inconsistency (ERA 4.12).
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2021–2023 – Clustered much tighter, typically 5.8–6.3 ft, with several clean groupings above 6.0. By 2023, most sessions showed stability in the 5.8–6.2 range.
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Trend: A taller, more vertical slot created improved fastball carry and reduced variability year-to-year.
Release Extension: Quietly Consistent
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2020: Typically sat between 4.5–5.5 ft, below league-average extension.
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2021–23: Stabilized between 5.6–6.9 ft, with many sessions in the 6.4+ range. By late 2022 and early 2023, Luzardo regularly extended 6.5–7.0 ft, nearly two feet farther than in 2020.
- Trend: Greater reach shortened hitter reaction time and enhanced perceived velocity, even if it wasn’t the primary driver of year-to-year ERA shifts.
Release Side: Closing the Cross-Fire
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2020: Wide cross-body release, often -3.0 to -5.0 ft from centerline.
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2021–22: Gradual shift inward; practice sessions clustered between -2.0 and -2.5 ft.
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Early 2023: Tightened even further around -1.8 to -2.2 ft, his most repeatable window.
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Late 2023: Some drift wider again (-3.0 to -3.4 ft), coinciding with a short rough patch.
- Trend: Reduced lateral drift improved command and predictability, helping him attack the strike zone more consistently.
Big Picture: By 2022–2023 Luzardo consistently delivered from a higher, more centered arm window, which became the mechanical foundation of his breakout. Luzardo systematically raised his slot, narrowing his side release, and extending further toward the plate. The exact recipe for more swing-and-miss.
In-Game Correlation: Practice Meets Performance
| Season | ERA / FIP | Notable Data Alignment |
| 2020 | 4.12 / 4.19 | High variability mirrored his scattered release height and wide lateral line. |
| 2021 | 6.61 / 5.48 | Continued searching for an arm slot, again reflected in practice volatility. |
| 2022 | 3.32 / 3.12 | First full year with tight 6.6–6.9 ft height and ~-2 ft side—and a major leap forward. |
| 2023 | 3.58 / 3.55 | Maintained that window for most of the year; brief dips in extension and side (-3 to -3.5) neatly match a mid-season slump. |
The Rapsodo sessions and the MLB stat lines tell the same story: mechanical consistency breeds run prevention and strikeout growth (208 K in 178.2 IP in 2023).
Connecting to 2025: Back to the Sweet Spot
The MLB.com feature explains that in 2024 Luzardo experimented with a higher release to chase extra “ride” on his fastball.
“I was trying to improve my four-seam a little bit more, get a little bit more ride with it, understanding that the higher slot kind of creates more carry,” Luzardo said. “But at the same time, it kind of hurt me in other ways. I don’t regret trying it out, but I understand that that’s probably not the best move for me.”
In the article, Luzardo himself emphasized that his new arm angle is central to his resurgence. The article cites:
- Added carry on his fastball from the higher release.
- Reduced predictability against hitters due to a tighter, over-the-top angle.
- Improved deception from added extension.
The Rapsodo metrics validate these claims, showing that what Luzardo describes matches quantifiable, year-over-year adjustments.
The measurable effect—four-seam induced vertical break (IVB) rising from ~14.1" in 2023 to ~15.4" in 2024—didn’t translate to better overall results or comfort. In 2025 he lowered the arm angle by roughly six degrees, returning closer to the 2023 slot and immediately regaining dominance.
The sweeper he now throws heavily (opponents ~.178 AVG, ~44% whiff) thrives with this more east-west movement, another by-product of the slightly lower, more natural release.
When overlaying practice trends with MLB stats, the connection is undeniable:
| Year | Avg. Release Height (ft) | Release Side (ft) | Extension (ft) | ERA | K/9 |
| 2020 | ~5.6 | -3.5 to -4.0 | ~5.0 | 4.12 | 9.0 |
| 2021 | ~5.9 | -2.5 to -3.0 | ~6.0 | 6.61 | 9.1 |
| 2022 | ~6.0 | -2.0 | 6.5+ | 3.32 | 10.8 |
| 2023 | ~6.2 | -2.0 | 6.5+ | 3.58 | 10.5 |
Key Takeaways:
- 2020–21: Wide, inconsistent mechanics → higher HR rate, inflated ERA.
- 2022–23: Stable higher slot and long extension → ERA drops nearly 3 runs, strikeout rate jumps.
- 2025 Outlook: With his new arm angle fully integrated, Luzardo projects as a true No. 2 starter or better.
Rapsodo Takeaway: the same high-resolution practice metrics that chronicled his earlier gains can also verify the wisdom of the 2025 adjustment—proof that real-time release monitoring is essential for making and validating changes.
Visualizing the Transformation
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Release Height: Climbed steadily each year.
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Release Side: Narrowed closer to centerline, improving repeatability.
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Extension: Jumped from ~5 ft to nearly 7 ft, maximizing perceived velocity.
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Performance Correlation: ERA fell as mechanics stabilized, while strikeouts rose in tandem.
Lessons for Pitchers and Coaches
1.) Define the repeatable window. For Luzardo that’s roughly 6.6–6.9 ft high and -2.0 ft lateral, with ≥5.6 ft extension.
2.) Use practice data as a guardrail. Quick feedback on release side drift or extension dips can flag subtle mechanical leaks long before they inflate an ERA.
3.) Chase fit, not just raw metrics. The 2024 experience shows that more IVB isn’t automatically better if it disrupts comfort or pitch-mix harmony.
Rapsodo Advantage
Jesús Luzardo’s evolution is a textbook example of how measured practice data leads to performance breakthroughs. By adjusting his release height, tightening his horizontal release, and lengthening his extension, he transformed from an inconsistent talent into a strikeout-heavy weapon.
With the MLB spotlight now recognizing his new arm angle as the key to 2025 success, Rapsodo data proves he’s been building toward this for years.
For pitchers at every level, Luzardo’s case underscores the value of quantifying release metrics and using them to unlock untapped potential.
By capturing thousands of release points per season, Rapsodo allowed Luzardo’s team to see and quantify the difference between “feel” and “real.” When he decided to lower his slot in 2025, they weren’t guessing. They had seasons of trusted evidence.
In short: Jesús Luzardo’s ascent underscores the value of precise, long-term release tracking. With Rapsodo’s practice data, coaches and pitchers can not only spot when an arm slot is working, but also have the confidence to return to it when experimentation goes too far.
What gets measured gets improved. Luzardo’s rise shows that tracking release metrics in practice isn’t just about numbers, it’s about unlocking the consistency that separates raw stuff from elite performance.
Interested in bringing this level of insight to your staff or program? Contact Rapsodo Baseball to learn how our pitch-tracking technology can turn every bullpen into a long-term development lab.
