It's time to have the Nestor Cortes conversation

In the first two games of a pivotal Yankees series in Houston on July 9-10, the home team failed to score at all. Gerrit Cole was the showstopper in the second game, hitting 99 mph on the 129th and final pitch of a complete game shutout. He's the ace though; we expect him to blow us away from time to time. The starter in the first game began the season in the minors with no expectations whatsoever. Nevertheless, Nestor Cortes' 4 2/3 shutout innings were par for the course he's been playing all season.

Cortes sort of snuck into the rotation. His first start was on July 4 in the second game of a doubleheader, but his brilliant performance five days later cemented him into the role. He certainly earned it with a 1.05 ERA over 25 2/3 innings and exactly 100 batters faced, striking out 31, and yielding just 15 hits, ten walks, and no home runs whatsoever.

You're forgiven if you didn't see his success coming. This is the 26-year-old's third stint with the Yankees organization. They selected him out of high school in the 36th round of the 2013 draft. The Baltimore Orioles plucked him away in the Rule V Draft prior to the 2018 season but returned him in mid-April after four disastrous appearances. He spent most of 2019 in New York, throwing 66 2/3 forgettable innings with a 5.67 ERA. They traded him to the Seattle Mariners for "future considerations" after the season, and he appeared five times for them in 2020 before becoming a minor league free agent. The Yankees knocked on his door once again in January, immediately assigning him to Scranton/Wilkes-Barre. They called him up to the Bronx on May 30 and he's been among their best pitchers over the last month-and-a-half.

No one gets big-league hitters out by accident— at least not for long. He's clearly doing something right. Let's dig into what he's done to earn Aaron Boone's trust so quickly and ascend from mop-up reliever to every-fifth-day starter.

Crafty Lefty

Sometimes a pitcher comes up from the majors with obvious appeal, pumping high 90s heat through the strike zone. Nestor Cortes' allure is more subtle. His four-seam fastball averages 90.6 mph, which certainly won't blow hitters away. As per Statcast, he also features a curveball, slider, and sinker which he'll throw to everyone as well as a changeup that he reserves just for right-handed hitters.

That fastball may not be very, uh, fast, but it sure is effective. His xwOBA (the expected success of a batter based on their quality of contact) is .182, which is the eighth-best in MLB on a four-seamer. In fact, almost all his pitches have been fantastic this season:

• Fastball: .121 BA, .212 SLG, .200 wOBA

• Curveball: .111 BA, .111 SLG, .130 wOBA

• Slider: .222 BA, .278 SLG, .303 wOBA

• Changeup: .313 BA, .375 SLG, .322 wOBA

• Sinker: .000 BA, .000 SLG, .000 wOBA

He's given up a few hits on the changeup— again, he throws that only to right-handed hitters— but not many for extra bases. Every other pitch stays pretty clean. Having five effective pitches (...or more— we'll get into that later) keeps his quality of contact down. He has allowed 85.8 mph average exit velocity, 3.4 percent barrel rate, and 28.8 percent hard-hit rate— all of which are much better than the MLB averages.

All pitchers need to hit their spots, but soft-tossers like Cortes need to be especially pristine with their command. He fills up the strike zone with a zone rate of 53.7 percent— well above the MLB average of 42.2 percent. Here's where he locates his fastballs:

Here's how he spots his breaking pitches:

All his pitches live on the inside and outside corners. His fastballs hit the heart of the strike zone more often than his breaking pitches. In any case, he's exceptional at throwing strikes yet but avoiding meatballs.

Off Balance

Any MLB hitter can crush a 90 mph fastball—even if it's well located— if they know what's coming. Nestor Cortes deploys several strategies to keep them guessing as much as possible. One way is by throwing any pitch in any count. This is his pitch mix when he gets ahead of batters:

Here's his pitch mix when he gets behind:

He tends to throw more fastballs and changeups when he's ahead of hitters than when he's behind, but it's not a drastic differential. Batters have to expect any pitch at any time.

Furthermore, his slight preference for breaking balls when he's behind batters is counterintuitive to the way most pitchers operate, also known as "pitching backward." Most hurlers go to a fastball when they need a strike, but he leans more on his slider and curve in those counts. In other words, he tends to give hitters more breaking pitches when they're looking for a fastball.

Statcast credits Cortes with throwing five different pitch types. If you were to ask him (or Gary Sánchez and Kyle Higashioka) how many pitches he throws, he'll probably have a difficult time answering the question. More than likely, the line between his four-seamer and sinker muddles. The same holds true for his slider and curveball.

A master finesse pitcher knows how to make slight alterations to his grip and arm action to throw a spectrum of fastballs and a myriad of breaking balls that blur definitions. Pitch tracking technology is a modern marvel, but it can't do him justice. Every breaking pitch must be put in either the "slider" or "curveball" buckets, but in truth, they're all variations and improvisations on the same theme. This prevents batters from keying in on his breaking pitch because that breaking pitch doesn't look the same way twice.

Slowing Down and Speeding Up

Another way he keeps hitters guessing is by comically varying his delivery. This was somehow a legal windup:

https://twitter.com/PitchingNinja/status/1403834182724370440

Here he's shown switching up his arm slots and release points:

https://twitter.com/PitchingNinja/status/1168650275978207232

The umpire wasn't having any of his balletic antics against Shohei Ohtani:

https://twitter.com/MLBONFOX/status/1410072434628349953

Here was the next pitch immediately following that disruption:

[video width="1280" height="720" mp4="http://bronxpinstripes.com/wp-content/uploads/2021/07/Nestor-Cortes-quick-pitch.mp4"][/video]

Ohtani, who had already hit two home runs that day, would end the shenanigans on the pitch after that one by flying out harmlessly to center. He was probably just glad to be done with the at-bat. After all, he can appreciate a pitcher's mind games as much as anyone.

Nestor Cortes' Lofty Comparison

There is another left-handed pitcher in the AL East who thrives at low heat, mixing up pitches masterfully and keeping batters guessing. Toronto Blue Jays ace Hyun-jin Ryu barely scrapes 90 mph with his four-seamer. He throws lots of different variations on both his fastball and breaking ball, as well as an excellent changeup. It's a recipe that made him a Cy Young finalist in both 2019 and 2020.

Nestor Cortes is posting Ryu-like numbers so far, but it has only been 25 2/3 innings. His major league resume prior to 2021 was did not portend such a rise to excellence. He could turn back into a pumpkin at any time, and odds are that he probably will. He's unlikely to pitch like Ryu forever, but as long as he can keep the American League off balance, the Yankees will take whatever he can give them every fifth day.