The Dan Warthen Slider and the Usage of the Slutter

Most people outside of New York probably do not know who Dan Warthen is. A former pitcher for the Expos, Phillies, and Astros, Warthen has been the pitching coach for the Mets since 2008. Hired under Omar Minaya, Warthen was one of two members of the coaching staff to survive the mass regime change following the 2011 season.

Putting the young ace pitching staff, the future of the franchise, into Warthen’s hands showed a lot of faith in the coach and he has risen to the occasion though the continued development and improvement of Noah Syndergaard and more importantly, turning Jacob deGrom from fringe prospect into borderline superstar.

Many, myself included, credit Warthen for this because he introduced a new pitch to almost his entire rotation and bullpen: a hard slider now known as “The Warthen Slider.” The grip is a slightly unorthodox slider grip, deeper into the palm and further away from the horseshoe of the stiches, the slider sweeps less but is much faster.

It is as much cutter as it is slider, for the dirtier minds we could call it a “slutter.” More on that later.

This singular pitch has done more for this rotation than almost any adjustment they could have made. This pitch has done wonders for Harvey and deGrom (Syndergaard has yet to master the pitch yet, only becoming truly confident in throwing it in September and October, moving from less than 1% to around 9%). All three of them thrive with their power fastballs, which has lead to concern about their health.

How can we maximize the power of the Mets pitching while avoiding late season fatigue? What if, for the sake of argument, we reconsider the philosophy of Mets staff’s use of the slider? In that instead of using the slider as a secondary breaking pitch we use it as a primary offering mixing it in more often with four seamers and two seamers more similarly to that aforementioned cut fastball?

The cutter was the pitch du jour mostly starting in 2011 and it seemed as though every single pitcher was beginning to add the pitch to their repertoires and for good reason. The movement would neutralize opposite handed batters similarly to how a good two seam fastball neutralizes hitters of the same handedness. It made pitchers overall more versatile and extended their careers.

Guys like Dan Haren and Roy Halladay both used cutters as their primary fastballs. Jon Lester, Corey Kluber, Johnny Cueto, Brandon McCarthy, Adam Wainwright, and Cliff Lee all threw the pitch more than 20% of the time (5% less than both Harvey and deGrom). Essentially, for all intents and purposes, their cutters were as equal a part of their arsenal as their four and two seam fastballs.

Let’s consider what would happen if the Mets starters began using the Warthen slider philosophically as more of a cutter, increasing usage to around 25–30%.

If we have a concern about arm health due to velocity, we’re using a pitch that is right in the wheelhouse of cutter velocity, about four miles per hour below the low range of their fastballs. In theory, this should cut the risk of arm injuries due to not throwing at max effort so much.

Throwing more of these slutters would keep hitters off balance and increase the effectiveness of their regular fastballs. While throwing the pitch more may slightly decrease the value of the pitch, it would increase the already prodigious value of their other fastball offerings, especially for someone like Harvey who mostly works with his fastball up in the zone.

Somewhat importantly as well, the pitchers can add or subtract to the velocity of the slider if necessary, which is something you can’t really do with a hard fastball. Modifying the grip ever so slightly by putting different pressures on the ball could add movement or velocity to the pitch as they need.

When it comes to his young staff, I understand that if something is not broken don’t fix it and clearly these young arms are doing something extremely right.

Yet, if we’re looking for different ways for the Mets pitching to evolve and stay healthy throughout the entire course of the season, perhaps it’s time to re-evaluate the amount of time the Mets staff use such a versatile and invaluable pitch.