It Shouldn’t Be Called “The Warthen Slider”

For the purpose of this exercise: Let’s say Major League Baseball, specifically the Mets, is the Matrix. Mets’ pitching coach Dan Warthen represents Morpheus and you, the reader, are a rookie MLB pitcher.

However, Warthen isn’t offering you a blue or red pill, rather he’s extending you a pitch (literally and figuratively). A delivery that might change your career. And you, fresh off a five-hour flight from Las Vegas, must make a decision.

Do I let Warthen teach me his trademark slider or do I trust my own stuff? Do I take the blue pill and keep all the knowledge and talent I already have? Or do I take the red one, and open myself up a world of all new possibilities, with the famed “Warthen Slider” now at my disposal. What is the best way to learn how to throw a slider?

That’s the dilemma many Mets pitchers faced during their first cup-of-coffee in the big leagues.

Nearly every homegrown pitcher that the Mets called up to the Majors during Warthen’s tenure as pitching coach was taken under his tutelage and taught the distinguished pitch. Matt Harvey, Jacob deGrom, Zack Wheeler, Noah Syndergaard, Robert Gsellman, Hansel Robles, to name a few.

Warthen was dismissed after the 2017 season, but his legacy lives on. Throughout the last decade, there’s been a litany of dominant starters in Queens. During their peaks, Harvey and deGrom were in the conversation for the best hurler in the sport. Syndergaard and Wheeler have each flashed ace-like potential. Jeurys Familia, Jenrry Mejía, and Gsellman have each anchored the Mets’ relief corps, at one time or another.

Both deGrom and Harvey credited the pitch for most of their success with Harvey, in a 2012 Fangraphs interview with David Laurila, saying, “[Mets pitching coach] Dan Warthen helped me out with the grip during Spring Training…. This year it’s the grip — throwing it like a fastball — and letting it work.”

Syndergaard added in a New York Post interview, ““I have that finger right up against the seam and rotate the ball on its axis,’’ Syndergaard said. “Thumb on the side allows you to get your fingers on top and then right at the last second it rolls off your fingers. I barely hold it. Just trust the grip and throw it just like my fastball. I try not to think too much.’’”

Warthen described it as, “It’s a different spin, it’s a different grip. The whole idea is not to use your wrist to try and spin the ball, you want your fingers to spin the ball. You’re thinking fastball and just kind of cutting through the ball.”

This unique grip gives the pitch its trademark tight spin and late break. But it also gives the pitch an additional element not usually found in MLB-caliber sliders: extreme velocity.

If you take a look at the hardest sliders in the game, you’ll find several Mets atop the list.

The abnormally high velocity is one of the many differences between the Warthen-taught slider and the average MLB one.

The “Warthen Slider” ranks middle of the pack in Savant’s Active Spin leaderboards, with Gsellman’s slider coming in as the most efficient at 33% while Robles’ brought up the rear at 18% (Remember: the lower, the better for sliders)

From a pitch movement standpoint, the “Warthen Slider” is thrown with a significant deviation in terms of overall vertical movement. Per Savant, several of Warthen’s disciples (Gsellman, deGrom, Familia, Seth Lugo, Robles, Corey Oswalt, and Wheeler, respectively) rank in the bottom 50 in terms of vertical movement.

Several other hurlers, albeit a lesser amount, of Mets also appear on the bottom of Savant’s slider movement board in terms of pure horizontal movement (Gsellman, Familia, Robles, Oswalt).

All in all, the “Warthen Slider” really isn’t a slider. Instead, the pitch’s traits classify it more as a cutter, rather than a slider.

I charted the movement profile of pitcher’s cutters and sliders added any Mets pitcher that threw the “Warthen Slider” into the mix. As you can see, these sliders are better grouped as cutters, rather than their original classification.

The orange dots represent the cutters of homegrown Mets who pitched for the team from 2016-2020, while the blue dots show other pitchers.

The group of orange dots in the bottom left in Group 2 are the Mets’, showing the lack of the comparable movement derived from the pitch. However, looking at the first graph, which compares cutters to the “Warthen Slider”, the movement profile of the Mets’ sliders are more in line to the movement profile of cutters.

In terms of seeing it visually, the “Warthen Slider” offers a unique perspective, compared to other sliders.

On the left is Jacob deGrom’s slider/cutter hybrid in BallR and on the right, is the average MLB slider.

For a more thorough description of this phenomenon, check out this piece I previously wrote about Jacob deGrom’s slider/cutter.

Whereas the typical MLB slider had 69 degrees of gyro spin, the Mets’ sliders differ. There was a four degrees difference in gyro degrees between an average 2019 MLB slider and the Mets’ ones. Granted, that’s not significant by any means, but it is notable.

Other factors, including spin efficiency, spin rate and release point, remained similar. But, according to Patrick Brennan’s Horizontal Attack Angle and Vertical Attack Angle calculations, the Mets’ sliders in 2020 had a small amount of VAA/HAA deviation from the league mean, although that’s not a conclusive measure since many other factors go into that.

Even though there has been plenty of pieces lamenting the usage of Warthen’s offering, I think the “Warthen Slider” is a net positive. Plenty of pitchers went on record to state they felt more comfortable throwing the new slider and Warthen has claimed that because the pitch is not thrown like a true slider, less stress is exerted on the elbow. A couple of hurlers have utilized the delivery on their path to stardom, in addition to going viral on Twitter.

It’s worth noting that free-agent starter Taijuan Walker just signed a two-year deal with the Mets. Walker’s another pitcher that has a slider/cutter in his arsenal and I’m intrigued to see how the Mets plan to utilize it.

Pitch classifications systems are funky. Some pitches that move like cutters are classified as sliders. The debate of what constitutes a change-up and splitter is still unresolved to this day. Hell, pitch classifications algorithms still can’t make heads-or-tails of Devin Williams!

Overall, the final say in a pitch’s classification falls on those who throw it. If Dan Warthen insists his trademark pitch is really a slider, then Statcast records it as such and it goes into the record books as such.

But I’m here to change that.

Cover Picture courtesy of MLB Trade Rumors