Everyone knows by now that a big part of what makes Noah Syndergaard's slider so good is its ridiculous velocity. The pitch sits around 92 miles per hour, making it the hardest slider for a starting pitcher in the PitchF/X era, and probably in baseball history. It has late, sharp break, which adds to the deception of a pitch mix because it looks the same out of his hand as a fastball to hitters. If hitters see it break early, they're more likely to identify where it's going and put a better swing on it, or lay off it if it's not going to be a strike.
Those two characteristics alone are enough to make it a dangerous weapon. But what completes his slider as one of the best pitches in baseball is his strong command of it. Syndergaard doesn't put the pitch in a place that a hitter can hit it well very often, and the location he often puts it in with two strikes is lethal.
This zone chart, from baseballsavant.com, illustrates the locations of Syndergaard's slider so far in 2016.
The majority of his sliders have ended up buried in that down-and-in zone to lefties and down-and-away zone to righties. The nature of a slider from a right-handed pitcher is to break near that zone. But what makes Syndergaard's pitch location so good is that his slider often appears to be a strike at first before breaking into that bottom-right zone, and combined with the hard velocity and deception, it's very difficult for a hitter to lay off chasing it.
Here's an example of that. Syndergaard will often start the pitch knee high on the outer half of the plate to right-handed hitters before having it break out of the zone.
When Syndergaard commands the hard slider that well with two strikes, it's incredibly difficult to lay off because the hitter has a tough time determining whether it's going to stay true at 98 miles per hour for a strike or break off the plate for a ball.
In Monday's start against the Reds, Syndergaard continued to attack hitters with sliders in that bottom right location.
Perhaps the greatest example of how difficult Syndergaard's slider is to identify at times is how he completely fooled Joey Votto, notorious for his incredible plate discipline, with a 3-2 slider that ended up in the dirt:
The slider looked like a strike at first to Votto before breaking well out of the zone. Getting hitters to think the pitch might be a strike when it's released from the hand is a big part of getting them to chase a breaking ball, and that's where Syndergaard's slider command comes in to mesh with his hard velocity and deception.
Syndergaard struck out right-handed hitter Devin Mesoraco on a similar slider location:
Both Votto and Mesoraco have their swing bases destroyed by Syndergaard's deception, lunging forward after being fooled, which helps explain part of the reason why it's difficult to get batted ball velocity behind contact on the pitch. According to statcast, his average exit velocity off his slider is about 74 miles per hour, significantly below the MLB average of about 86 miles per hour on sliders.
This is an exit velocity zone chart for Syndergaard's slider, also from baseballsavant.com.
Syndergaard's slider has only been hit well twice, most glaringly on a slider that hung middle middle to Peter Bourjos on a line out to center field, only one of three sliders Syndergaard has left middle-middle all season. The other balls in play have generated extremely weak contact: none was struck at more than 94 mph, and most have been less than 85 mph. To hit a home run, a batter will generally need to generate a minimum of 95 mph on a batted ball, and often over 100 mph.
Where Syndergaard puts his slider has affected the trajectories on it, too. Syndergaard's slider has only been put into play 16 times in 2016, 10 of which have been weak ground balls, a 63% rate. The only fly ball he allowed on a slider was a weak pop-up, which almost always goes for an out; the league hit .021 on pop-ups in 2015. By limiting well-hit fly balls off his slider, the chances of him giving up extra-base hits on the pitch goes down tremendously. With the amount of hard sliders he commands at the bottom of the zone, it's easy to see why hitters have a very difficult time getting any lift on the pitch.
So while Syndergaard's slider velocity and late break generate the most eye popping appeal, watch out for his command of it, too. It's what completes the pitch as, maybe, the best pitch in baseball right now.