90.5 MPH – .184 wOBA – .163 xWOBA – 27.1% whiff rate
Yeah, we just started an article with stats. That’s how good the numbers are on Nestor Cortes’ fastball, which may just be the most underrated pitch in baseball right now.
With Corey Kluber and Luis Severino rehabbing from injury, Nestor Cortes has stepped into the rotation and been nothing short of a revelation. By the numbers, no pitcher has a better performing four-seam fastball than Nestor Cortes, which is a crazy sentence to write. Cortes has won four starts in a row and holds a 2.15 ERA while pushing the Yankees to only 1.5 games back of the Wild Card. Cortes baffles hitters with Johnny Cueto-esque variations to his windup paired with one of the most efficient pitches in baseball.
The Fastball Landscape
The average MLB fastball is almost 94 MPH. In not so shocking news, the data shows that increasing fastball velocity is correlated with increased whiff rates and weak contact. Below is a chart displaying average four-seam velocity and whiff rate. The trend line shows a positive relationship between velocity and whiffs.
Many of the best fastballs top out at 100 MPH or more. Zach Wheeler, Jacob Degrom and Gerrit Cole average over 97 MPH on their four-seamers, which is well above the MLB average fastball at 94 MPH. There are 594 pitchers that have thrown at least 100 pitches this season. 241 of them average more than 94 MPH and 526 (88.6%) of pitchers average more than 90.5 MPH, the average velocity of a Nestor Cortes fastball.
Deception over Velocity
So if more velocity means more whiffs and Cortes is in the bottom 12% of the league in that regard, how is his fastball so good? Well, there’s more to pitch design than just velocity. The secret to the deceptive nature of Cortes’ fastball is well above league average vertical movement. At 14.6 inches of vertical drop, Cortes gets 2.4 inches less drop on his fastball than league average 88-92 MPH fastballs.
In short, Cortes gets more “rise effect” on his fastball than other pitchers that throw the same velocity by getting on top of the baseball with an almost perfectly horizontal spin axis and optimal spin efficiency. Hitters expect the ball to drop more than it does, so barrels get under the baseball. This leads to a high percentage of weak fly balls.
Cortes ranks 27th in average launch angle at 22.4 degrees, and among pitchers that throw four-seamers at least 20% of the time, Cortes gives up the 17th lowest amount of hard contact at 32%. Watch as Abraham Toro swings right under a Cortes fastball for a punch out below.
The Best Fastball in the Land?
I know what you’re thinking, how is it really possible that Nestor Cortes has the best fastball in baseball? Among pitchers with more than 50 batted ball events against their fastball, Cortes ranks first in wOBA, xwOBA, batting average, and expected batting average against. Absurdly, those figure ranks his heater just above Josh Hader’s fastball. By run value per 100 pitches, which gauges run expectancy against, there are only 15 pitches more productive at reducing run scoring on a per-pitch basis than a Nestor Cortes fastball.
The natural evolution of pitching has led us down a path focused on velocity over anything, but pitchers like Nestor Cortes prove that deceptiveness, in the form of movement and varied deliveries, can lead to success even with the 24th lowest four-seam fastball velocity in baseball.