Remedying Jesus Luzardo's dead zone fastball
- jagreens
- Dec 13, 2024
- 6 min read
As per tradition around this time of year, Jesus Luzardo is generating trade buzz. The Marlins enigmatic left-hander took a step backwards in an injury-plagued 2024 season, on the heels of a career year in 2023.
The biggest discrepancy between 2023 and 2024 was Luzardo’s four-seamer, which devolved from strength to weakness:
Luzardo’s FF | wOBA | xwOBA | RV/100 | Swing% | Whiff% | Velocity |
2023 | .301 | .350 | 1.1 | 50.2% | 19.4% | 96.7 mph |
2024 | .367 | .390 | -0.3 | 46.6% | 11.1% | 95.2 mph |
In 2023, Luzardo succeeded despite having a classic dead zone fastball. His four-seamer had identical vertical and horizontal movement, with 14.0 in. of IVB and 14.1 in. of armside run. It also had a 10:30 spin direction.
Hitters expect a pitch to behave a certain way out of the pitcher’s hand; the more a pitch moves like expected, the worse it performs. With average movement and prototypical dead zone spin direction, Luzardo’s four-seamer moves as expected. We can see this through the following Pitch Plot courtesy of TimStats, which takes into account one standard deviation.
It’s possible to succeed with a dead zone fastball, and Luzardo did so in 2023. But, heading into 2024, he made a series of changes to his four-seamer, perhaps with an eye towards escaping the dead zone.
For one, he raised his arm angle (35 degrees → 39 degrees), throwing from a more traditional three-quarters slot. Austin Marchesani’s study for Iowa Baseball demonstrated that a pitcher’s dead zone varies for different arm angles. Pitchers with lower three-quarters slots have a dead zone for fastballs with more horizontal break than vertical break. Luzardo, notably, changed his four-seam shape in the other direction.
Luzardo FF, 2023: 14.0 IVB // 14.1 armside run
Luzardo FF, 2024: 15.3 IVB // 13.1 armside run
If we adhere to Marchesani’s concept of a revised dead zone, the shape change — more rise, less run — would have been more effective had Luzardo continued to throw from a lower three-quarters arm slot.
Max Bay’s Dynamic Dead Zone app allows us to visualize the difference between a fastball’s actual movement and its expected movement, based on a pitcher’s arm angle. In the following screenshots, we can see that Luzardo’s four-seamer was slightly more predictable in 2024 than 2023.
So the added IVB, while good on the surface, proved mostly moot. Something else happened to Luzardo, too: He lost a ton of velocity:
Luzardo FF velo. 2023: 96.7 mph
Luzardo FF velo. 2024: 95.2 mph
Velocity is one of the best known countermeasures to a dead zone fastball (the other being spin deviation). It’s even more paramount for Luzardo, whose fastball has always played down. Look at this from FanGraphs, back in 2019:
“[Luzardo’s] fastball may not play like a mid-90s heater because he’s undersized and a short-strider, but he locates it well enough to avoid getting hurt.”
We’ll hit on all of that in a second, but let’s start with velocity. Luzardo has experienced a gap of at least 1.2 mph in actual velocity and perceived velocity in every single season since his MLB debut in 2019. In 2024, his four-seamer averaged 95.2 mph; in perceived velocity, that graded out to just 93.8 mph.
As such, any drop-off in velocity is especially detrimental to Luzardo.
FF success by velocity bands, since Luzardo debuted (‘19) | >= 96 mph | 94-95 mph |
Luzardo | .316 wOBA | .582 wOBA |
MLB | .295 wOBA | .341 wOBA |
The average MLB pitcher is hurt significantly less by a slower four-seamer, largely because Luzardo’s 94 looks more like 92. In fact, since he entered the league, no left-handed starter throws harder with a greater differential in actual and perceived velocity than Luzardo.
Actual Velocity | Perceived Velocity | Difference (Actual-Perceived) | |
Caleb Smith | 91.5 mph | 89.6 mph | 1.9 mph |
Drew Pomeranz | 92.0 mph | 90.0 mph | 2.0 mph |
Ross Deltwiler | 91.7 mph | 90.2 mph | 1.5 mph |
Justin Wrobleski | 94.9 mph | 93.3 mph | 1.6 mph |
LUZARDO | 96.1 mph | 94.8 mph | 1.3 mph |
Why does Luzardo’s fastball play down? Part of the reason is his poor extension, which grades out in the fourth percentile. A short extension means the pitcher is releasing the ball earlier, allowing the hitter more time to see the ball on its way to the plate. Hitters have more time to react to Luzardo’s fastball than they do with most other pitchers.
In and of itself, playing down isn’t necessarily an issue. Drew Pomeranz, for instance, carved out a successful late-career role as a reliever, largely because of exceptional IVB. Therein lies Luzardo’s problem. He has a dead zone fastball and velocity that plays down — and, in 2024, lost his velocity all together. The combination of these traits is difficult to overcome.
The effect of these qualities is best measured through Vertical Approach Angle (VAA), which quantifies the intersection between velocity, pitch height, and release point on a specific pitch. In 2021, Alex Chamberlain concluded that outlier VAAs are en vogue, largely because they play an outsized role in generating whiffs. That would make sense: If hitters expect a pitch to behave a certain way, any unique combination of velocity and release point would stand to catch them off guard.
A year later, Chamberlain modified the statistic to normalize for pitch height, weighing only velocity and release point. Irrespective of whichever statistic you prefer, Luzardo went backwards in 2024:
Luzardo 2023 | Luzardo 2024 | MLB Average | |
VAA | -4.8 degrees | -5.2 degrees | -4.9 degrees |
VAA Above Average | -0.02 degrees | -0.20 degrees | 0 degrees |
Even though Luzardo modified his release point slightly, the drop-off in velocity mitigated that change. Rather than touting an outlier four-seamer, Luzardo’s is remarkably average — and trending in the wrong direction.
A flatter four-seamer — quantified by a VAA close to zero degrees — plays best at the top of the zone, where Luzardo likes to throw his four-seamer to opposite-side hitters. Luzardo’s four-seamer was less flat in 2024, and these pitches induce less wings and, expectedly, less whiffs.
Not only did Luzardo’s four-seamer become a drop steeper, but he struggled to hit his spots. This may be most consequential. As mentioned earlier in the FanGraphs scouting report, Luzardo’s four-seamer is successful in part because of his pinpoint location.
What we see with Luzardo is a complete snowball effect. He had good intentions behind his initial modifications, designed to draw his four-seamer out of the dead zone. But, in doing so, it appears he may have been pushing the baseball, sacrificing velocity to chase IVB. In the process, his location grew erratic, too. On top of that, when redesigning its shape, he seems to have considered the traditional definition of a dead zone, rather than one that considers arm angle. All together, Luzardo lost the traits that allowed his four-seamer to succeed in spite of its other damning qualities.
I wonder where Luzardo takes his four-seamer from here. I’d like to see the impact of his shape changes with added velocity, but there’s a chance those two are irreciprocal, if he was pushing the ball. In that case, he should prioritize velocity — as he’s shown in the past, with the right combination of velocity and location, he can succeed in spite of a dead zone fastball.
Luzardo’s season ended in mid-June due to a lumbar stress reaction, so we didn’t get to see his full transformation play out. I’m curious, though, if he made any adjustments before he got hurt: The velocity drop-off was apparent since the beginning of the season, and his four-seamer was never as effective as it was last year. If he did, these adjustments could give us a glimpse of what path he may pursue heading into next season.
Let’s start with right-handers, who pounced on his four-seamer in May and June. Sure enough, Luzardo relied more heavily on his changeup, which overtook his four-seamer as his No. 1 option. Against left-handers, who attacked his four-seamer from the get-go, Luzardo went to his slider, which became his No. 1 option in May. So by June, his four-seamer had become a secondary option against both lefties and righties. That feels like the right short-term approach, though I doubt its longevity.
A good comparison to Luzardo would be Wandy Peralta, a veteran left-handed reliever with a similar fastball, in terms of velocity and its dead zone nature. In 2018, Peralta first ditched his four-seamer as a top option; in 2022, he went to a sinker, leaving the four-seamer as a fourth pitch. After early-career struggles, Peralta has found tremendous success. Could Luzardo succeed as a starter with a four-pitch mix and a non-dominant fastball? Unless he reverts his four-seamer back to its past self, perhaps he profiles better as a reliever.
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