“Nasty Nestor” Has Baffled Hitters and Helped Salvage the Yankees’ Season

The Yankees’ 13-game winning streak came to an end in Oakland on Saturday, as a lineup that had been cranking out nearly seven runs per game for over a week had its bats silenced, and as starting pitcher Nestor Cortes bore the brunt of a questionable call or two, as well as some bad luck. It wasn’t his day, but that doesn’t diminish the job he’s done at the back of a banged-up rotation. Like many far better paid and more heralded players, the 26-year-old lefty has helped save New York’s season from oblivion, and in doing so, “Nasty Nestor” has carved himself a place in the majors while earning cult status.

Currently in his third stint with the Yankees, Cortes cuts an unassuming figure on the mound at 5-foot-11 and 210 pounds, armed a fastball that averages just over 90 mph. Those numbers belie the athleticism and inventiveness of the Cuban-born southpaw, who has taken a page from the playbook of countryman Orlando Hernandez by coming at hitters from a variety of angles, speeds, and arm slots, with the occasional hesitation thrown in for good measure.

Thanks to his creativity, Cortes has posted a 2.77 ERA, 3.59 FIP, and 25.6% strikeout rate, generating a whole lot of soft contact in his 61.2 innings. In doing so, he’s helped to compensate for injuries to Corey Kluber, Domingo Germán, and Michael King, as well as the prolonged absence of Luis Severino, and to lift the Yankees from their .500-ish nadir into a spot atop the AL wild card race.

It’s a big change from the outset of the season, when he appeared to offer the Yankees little more than organizational depth as a semi-familiar face on his third go-round with the organization. Drafted in the 36th round in 2013 out of a high school in Hialeah, Florida (where his father had moved the family from Cuba after winning a visa lottery when Cortes was still an infant), he was lost to the Orioles as a Rule 5 pick in December ’17. He made just four appearances for them in the first two weeks of the 2018 season, though, before being returned.

Cortes spent ’19 shuttling between Triple-A Scranton/Wilkes-Barre and the big club, getting added to the big league roster eight separate times. Working almost exclusively out of the bullpen, sometimes as a bulk guy and other times as a mop-up man, he didn’t pitch very well. In 33 appearances (including one opener-type start), he was rocked for a 5.56 ERA, 5.56 FIP, and 2.16 homers per nine in 66.2 innings.

Needing to create space on their 40-man roster in advance of the Rule 5 draft, the Yankees traded Cortes to the Mariners on November 25, 2019. While he made Seattle’s roster out of summer camp, he pitched just five times; in the last of those, his lone start, he was blitzed for eight runs and retired just one of the nine hitters he faced. He spent the remainder of the season on the injured list due to an elbow impingement and elected free agency after being outrighted off the 40-man roster in late October. In January, he returned yet again to the Yankees, this time on a minor league deal that included a non-roster invitation to spring training. Given his career 6.72 ERA and 6.69 FIP to that point, you could be forgiven for not noticing.

Cortes began this year back in Scranton, his fifth season out of the past six spent in Dunder Mifflin country. He was called up on May 30, the same day that the Yankees demoted Deivi García after a second unimpressive spot start and four days after Kluber joined Severino on the 60-day injured list. Despite a 1.20 ERA and 18-to-1 strikeout-to-walk ratio in 15 innings at Scranton, Cortes appeared likely to be part of the endless roster churn at the back of the pitching staff.

Yet he stuck around, spending his first month with the team as a multi-inning reliever and pitching well, too. In 17.2 innings spread over seven appearances, he allowed just 11 hits and three runs (two earned) and struck out 25 (35.7%), good for a 1.02 ERA and 1.69 FIP. On June 12, he entered in the first inning after Jameson Taillon had allowed four runs, stranded the two runners he inherited, and threw 3.2 innings of one-run ball, striking out six. A week later against the A’s, he tossed three scoreless innings in relief of Germán, holding down the fort as the Yankees rallied for a comeback win.

Cortes joined the rotation ahead of the second game of a July 4 doubleheader against the Mets just as the Yankees’ season was hitting bottom at 41–41 and a season-high 10 games out of first place in the AL East. He turned in 3.1 innings of one-run ball to help secure a split, then followed up with 4.2 innings of shutout work against the Astros five days later, stretching out to 74 pitches.

A breakthrough COVID infection landed Cortes — one of six Yankees sidelined during an outbreak — briefly on the IL, but since coming back (and aside from a messy relief appearance that marked his first action in two weeks), he’s been in the rotation ever since, giving the team 42 innings over his past six starts, all of them at least five innings. The stretch included games against the Rays, Mariners, White Sox, and A’s, with Cortes holding each to two runs or fewer.

In all, after producing -1.1 WAR in his 79 innings from 2017 to ’19, he has mirrored that with 1.1 WAR in his 61.2 innings. His showing won’t win a Cy Young award, but it’s come at a crucial time. During a stretch when the Yankees lost Germán to the IL to shoulder inflammation and both Gerrit Cole and Jordan Montgomery to the COVID-19 IL, they have won six of Cortes’ eight starts and 35 of 49 games since he joined the rotation.

So how did Cortes go from a Quad-A palooka to a cornerstone with his own t-shirt and a cult following? It hasn’t been by overpowering hitters, though he’s gained velocity on all of his pitches since debuting in 2018:

Via Statcast, Cortes averaged just 87.9 mph with his four-seamer when he first reached the majors, but he’s now up to 90.4 mph. That average conceals a substantial spread; he’s thrown four-seamers as slow as 86.7 mph and as fast as 94.3 mph. In consecutive plate appearances against Bryce Harper on June 12, he threw an 87.2-mph fastball in the second inning (his second-slowest of the season) plus a pair at 89.3 and one at 90.9, then came back to strike him out in the fourth looking at a 93.7-mph heater (his second-fastest of the year).

Relative to his 2018 debut, Cortes has also gained 2.4 mph on the average velocity of his changeup, 3.1 mph on his curve, and 2.9 mph on his slider (2019–21, since he threw it just once in ’18). His spin rates (2,203 RPM on his four-seamer, 2,436 on his curve) are below-average, ranking in the 39th and 47th percentiles, respectively, according to Statcast, but he’s getting very different movement on his pitches than he did in 2019:

Nestor Cortes Jr. Pitch Usage and Movement
Year FF% FF Drop FF Break CU% CU Drop CU Break SL% SL Drop SL Break
2019 45.9% 17.0 6.9 4.2% 52.6 6.5 31.4% 38.2 5.3
2021 43.2% 14.9 5.3 21.6% 41.4 14.5 22.0% 31.9 5.5
SOURCE: Baseball Savant
Drop and break measured in inches.

Cortes threw his curve more often during his brief 2018 and ’20 stints (26.9% and 17.6%, respectively) than in ’19, but what he’s throwing now is basically a different pitch, one that gets so much more horizontal movement that Pitch Info labels it a slider (and calls his slider a cutter). As he told the New York Post’s Ken Davidoff earlier this month, “In spring training, I wanted something sweepier, something bigger. The Yankees pitching staff helped me out to try to create this pitch.”

To that different pitch selection and movement, you can add Cortes’ tendency to vary his release point, particularly on the fastball and the curve (I’ve relabeled this Pitch Info-driven graph to conform with the Statcast pitch IDs):

Here, for example, is Cortes retiring Shohei Ohtani on curveballs on back-to-back nights as a reliever on June 28 and 29. The first time he faced him, he released the pitch at 5.05 feet off the ground and induced a weak grounder:

The next night, he dropped down, releasing the pitch at 4.11 feet — his lowest point of the year for the pitch, about 11 1/4 inches lower than the highlighted pitch from the previous night. Ohtani hit it at 100.2 mph, but it was nonetheless a routine flyout:

No big deal, just retiring the presumptive AL MVP from two different decks of Yankee Stadium, as one does. Here’s a side-by-side comparison of the two release points:

As for the fastball, here’s Cortes coming over the top to the Rays’ Brandon Lowe on July 28, with a release point of 5.85 feet:

And here he is dropping down against the Twins’ Luis Arraez on August 20, with a release point of just 5.21 feet (about 7 3/4 inches lower, and also about eight inches further to the first base side):

Pretty slick.

Where batters pulverized Cortes’ old curve for a .615 AVG and .846 SLG in 2019, accompanied by a mere 7.7% whiff rate, that’s down to .262 AVG and .500 SLG and up to a 24.7% whiff rate. That improvement conceals a drastic platoon split: righties hit the curve for a .136 AVG/.273 SLG, lefties for a much less helpful .400 AVG/.750 SLG. Good thing only 27% of the batters he’s faced this year have been lefties.

Meanwhile, where Cortes’ fastball was hit for a .264 AVG/.549 SLG in 2019, batters haven’t been able to do nearly as much with it this year, with a .165 AVG/.258 SLG — and that one holds up despite batter handedness, with a .188 AVG/.344 SLG against lefties and .154 AVG/.215 SLG against righties. It’s not as though he has been particularly lucky with the pitch, either; his .157 xBA and .260 xSLG are very close to his actual marks. Overall, he’s shown a reverse platoon split, with lefties hitting him at a .242/.288/.435 clip overall, compared to righties’ .200/.273/.315.

Add it up, and while Cortes is getting just a 9.2% swinging-strike rate and 26.3% CSW%, both of which are actually lower than his 2019 work, he’s doing a great job of limiting hard contact. Batters are averaging an 88.2 mph exit velocity (64th percentile) against him, with a 34.5% hard-hit rate (78th percentile) and a 4.8% barrel rate (90th percentile). His 2.89 xERA not only puts him in the 89th percentile, but it also matches that of Cole, who’s got the kind of stuff Cortes can only dream about.

Indeed, Cortes has staked his claim to a rotation spot alongside Cole, Montgomery, Taillon, and the freshly-returned Kluber, outpitching trade deadline acquisition Andrew Heaney and likely pushing Germán, King (who’s been out with a finger injury), Severino (if he ever returns from his umpteenth post-Tommy John surgery setback) and rookie Luis Gil (who earlier this month made history by throwing scoreless starts in his first three outings over 15.2 innings) to the bullpen. Even if the lefty winds up in a more flexible role down the stretch, he’s clearly earned a spot in the Yankees’ plans. Not bad for a Rule 5 pick who couldn’t cut it with the Orioles.

Brooklyn-based Jay Jaffe is a senior writer for FanGraphs, the author of The Cooperstown Casebook (Thomas Dunne Books, 2017) and the creator of the JAWS (Jaffe WAR Score) metric for Hall of Fame analysis. He founded the Futility Infielder website (2001), was a columnist for Baseball Prospectus (2005-2012) and a contributing writer for Sports Illustrated (2012-2018). He has been a recurring guest on MLB Network and a member of the BBWAA since 2011. Follow him on Twitter @jay_jaffe.

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Yay, the Nestor article! He’s a joy. And I keep thinking he’s going to get blown up one of these starts but it just doesn’t happen. El Duque is a good comparison for a “who? what? why is he doing that?”