Is Dinelson Lamet's Curveball Really the Key?


Published: Gaslamp Ball

Ninety-five percent of Dinelson Lamet's repertoire is composed of two pitches. You probably had some idea of this statistic, given your willingness to read about a pitcher on the San Diego Padres. (No, Fernando Tatis Jr. has not been called up yet.)

Common practice in searching for breakouts is to cite something a pitcher has changed as reason for expecting improvement. Grip, velocity, mechanics, and the easiest to write about, pitch mix, are some of the fields for potential alteration. Add thischange that, and the distance between said player and stardom will contract. The reason Lamet has become a topic of intrigue during spring is because of his simplicity. Offering only two pitches - a fastball and slider - he produced a league average season with an impressive strikeout total. How quickly one can understand what Lamet currently does versus hitters makes it easier to envision the curveball he has added coming to life and his difficulties disappearing. Take a five-pitch pitcher like Mike Leake, tell me one thing changed, and I would have to unravel everything he does to come to some conclusion. Studying Lamet's approach removes the need for isolation of variables to understand the true picture of what tinkering can do.

The difficulties holding Lamet back appear in two forms: on his third time through a lineup and against left-handed hitters. Both are extremely common issues for right-handed pitchers, especially those still younger than 27 years.

Visually, it's easy to understand Lamet's first difficulty.

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The larger theme embedded within the above chart is the league-wide shift to limiting starters' innings. Lamet isn't the only pitcher trying to solve issues like this. His aggregate batting average against ticks up to .270 versus right-handed hitters and .356 versus left-handed hitters after he's retired 18 batters. The former shows how effective he is to right-handed hitters, the latter highlights difficulty number two.

Most pitchers have natural platoon splits - for right-handed pitchers with two pitches this means left-handed hitters are a perpetual crux. Pitching is deception and deception is achieved from unexpected movement (simplified definition). Provide various options for a hitter to consider and it complicates his split-second decision making. Naturally, left-handed hitters have a much better time picking up a ball thrown from right-handed pitchers, making the need for deception on the pitcher's end even more vital. If those same left-handed hitters know 95 percent of the time, they're going to see a fastball or slider - even if that slider is really good - it limits how effective Lamet can be.

The natural suggestion is to give Lamet a third pitch, which the Padres have done with the curveball I mentioned in the opening, but this fix has left me wanting more, which stands in contrast to those who believe this is the key to another step forward.

Oddly enough, Padres pitching coach Darren Blasley admits to The Athletic's Dennis Lin that he isn't sure whether Lamet needs a third pitch at all; Lamet's slider is that great. It sits above the 75th percentile across the league in both horizontal and vertical movement, achieving a rare combination of whiffs and grounballs few others have. Blasley's comment was meant to highlight Lamet's success with simplistic options. If the Padres are looking for a league-average starter with substantial strikeout upside and sub-par control - harder to find than one would think - they have it. But improvement doesn't need to have an endpoint.

The same Dennis Lin article linked above provides more context to Lamet developing his curve. Lin touches on the hurler's ability to jump between hard and soft with this pitch, varying the velocity. The hard curve blends with his slider and the soft curve resembles the more traditional offering, with more vertical drop and depth. What interests me substantially more, however, is Lin's mention of Lamet continuing to work on his changeup.

Considering the addition of a curveball, in a binary sense, fulfills the notion that yes, there is a new pitch. But my general worry is whether this is the right pitch. If this slower curveball is at least average, I admit it will aid his effectiveness the third time through an order by simply providing more options, but it doesn't give me confidence that Lamet's problem with left-handed hitters has been fully addressed. My worry stems from both Lamet's secondary offerings still breaking in to left-handed bats. The addition of a curveball to the repertoire of a fastball-slider pitcher is also relatively uncharted territory. We have various two-breaking-ball pitchers, Jon Gray is a good example, but he, like others in this category, still offer an average changeup to left-handed hitters.

Given what the metrics say, Lamet's changeup is a weird pitch, so much so that I want to see more of it.

Velocity Diff - fastball velocity minus changeup velocity, 7-10mph is ideal; HMvmt - horizontal movement -6.7 is average for RHP; VMvmt - vertical movement 4.1 is average; Rel. Dist LHH - tunneling metric, release point differential of fastball-changeup sequence, lower is better, 2.6 is average; FG pitch Value - Fangraphs pitch value, 0.00 is average.

Velocity Diff - fastball velocity minus changeup velocity, 7-10mph is ideal; HMvmt - horizontal movement -6.7 is average for RHP; VMvmt - vertical movement 4.1 is average; Rel. Dist LHH - tunneling metric, release point differential of fastball-changeup sequence, lower is better, 2.6 is average; FG pitch Value - Fangraphs pitch value, 0.00 is average.

Most interesting in the batch of data points above is how hard Lamet's changeup actually is, essentially becoming a two-seam fastball, but possessing enough changeup-like qualities that we still consider it an offspeed pitch. "Rel. Dist LHH" shows Lamet's changeup release point is mimicked very well compared back to his fastball, which is perhaps one of the reasons this pitch is only five miles per hour slower than his four-seamer.

Everything we know about changeups tells us that Lamet needs to pick one end of the spectrum with the pitch. Either move towards a ground-ball offering with a higher velocity and seven mph separation from his fastball, or move towards the whiff route, which given the current characteristics of his pitch, might be too ambitious.

While it seems Lamet is embracing the grounball approach with his changeup, there aren't many pitches considered changeups in baseball with this low of a speed differential off a fastball. In a way, it might be hampering the ground-ball nature of the pitch to be so close in velocity to his fastball. If Lamet found a way to remove 2-3 mph from the pitch, putting it in the 7-8 mph differential window instead of the 5-6 mph range, hitters might have a substantially harder time getting under the pitch, giving Lamet a combination of groundballs and strikeouts others would envy.

My unsubstantiated suggestion is that Lamet might be able to tinker with his release point on this pitch to take velocity off. As the lone tunneling metric shows, it may be too similar to his fastball to result in a pitch different enough to fool a hitter. Looking at some video of the pitch, it feels like the offering is constantly in between where Lamet wants it to be.


Moustakas' swing is what Lamet doesn't want, with any pitch. Markakis' swing goes for a base hit, but this topping of the ball is what Lamet needs for the pitch to fulfill my hopes and dreams. It's harder to discern the effectiveness of a hard changeup due to the lack of perceived drop and fade, especially up in the zone. Often with the naked eye, one can pick a changeup when a pitcher throws it. The difficulty you might have even realizing the two pitches above are changeups support the point I've tried to make: his changeup needs alteration.

We often hear about changeups being "feel" pitches, which relates to multitude of factors from how often the pitch is thrown to the pitcher's comfort with the pitch. The word comfort there is key. I could make all the suggestions in the world, each of which from behind this computer, not taking into account the steps the Padres have likely taken to address the matter. If Lamet is comfortable with his curveball, then my ambition for him figuring out his changeup is for naught, regardless of if I think the pitch won't make him substantially more effective to left-handed hitters.

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Lamet and the Padres know best. I still reserve some irrational hope that his changeup emerges over this curveball in-season.

Lance BrozdowskiComment