Some things in this world are not meant to go together. Sure, some people have unique preferences, but it’s fair to say orange juice and toothpaste are an odd couple. No sane person can convince themselves that that’s a good pairing. Orange juice is delightful, tangy, and a sweet way to start your day. The highlights of orange juice don’t undermine how important it is to brush your teeth, it’s just that everything about orange juice destroys what toothpaste tries to build up.
Replace the words “orange juice” with slider and “toothpaste” with fastball, and you’d have every baseball coach befuddled (also it’d be weird to describe a slider as tangy and sweet). To a baseball coach, they go together like peanut butter and jelly. Thanks largely to tunneling, sliders and fastballs are one of those things in this world that go together beautifully. Good tunneling has two different pitches look exactly the same until the point when a batter decides to swing or not. As you’ll see, it’s not just the release point that affects the quality of the pitcher’s tunneling. Pitches that look like they’ve got great stuff may not perform as well as you’d expect. The culprit for the underperformance is likely the difference in velocity and break of those two pitches.
Tieran Alexander, a former writer for Prospects Live, and other researchers have concluded that a pitcher’s slider and fastball and should have the following qualities: 6-14 inches of induced horizontal break separation, 8-16 inches of induced vertical break separation, and 6-11 miles per hour of velocity separation. If you don’t have the time or desire to check out his work on pitch tunneling, have no fear. Alexander used regression to find out which horizontal movement differences had the greatest chase rates and did the same for vertical movement and velocity. There are definitely exceptions, but there is also an ideal range for each of the three factors that had the most consistent success.
Having too much or too little of a movement difference makes pitches easier to identify and predict. Velocities that are too similar mitigate the intended timing disruption between a fastball and a slider. The consequences of these shortcomings often reflect in bloated ERAs and WHIPs. That has not been the case for Tyler Mahle so far this season. Mahle currently sports a 3.32 ERA, which is actually worse than his expected 3.23 ERA.
Considering he has roughly 20 inches difference of induced vertical break separation and 18 inches of horizontal, this could be considered somewhat surprising. Tyler has had a successful MLB career, but pitching is not static. There are always incentives to change and new pitches to master, just look at Emilio Pagán‘s inconsistencies, and that brand-new sweeper Pablo López has as proof. Some day, Mahle may decide to address his large gaps.
If that is the case, he would not need to adjust either of those two pitches at all. And he goes about it as easy as it could possibly get. No need to alter grips, movements, or thought processes. The key to getting the most out of his fastball-slider pairing is his cutter. The same cutter he has always thrown dating back to his Cincinnati days. Having a pitch in the middle ground of those two changes the batter’s approach, but does not affect him all that much. Sure, he’ll have to ensure he throws his cutter enough for it to be a true secondary offering. But as long as he uses it regularly, batters will have to honor it.
The reasoning behind this is simple. His slider may not look all that like his fastball, but both of them look like his cutter. The same effect sliders have based on fastballs applies to sliders based on cutters. Ditto for cutters based on fastballs. Oddly, Mahle has thrown his cutter significantly less this season. Although it has only been over the course of four starts, its usage will be worth monitoring. With decreased usage, the concern is that batters will catch on and be able to identify his slider and fastball easily and make sound swing decisions.
As mentioned earlier, the situation is not dire. Mahle is currently clicking and has located all four of his pitches well. His splitter in particular has fared exceptionally well at garnering swings-and-misses this season with a 41.2% whiff rate. Mahle always have his high-quality high-spin fastball. He’ll look to string along another quality start on Thursday against the Kansas City Royals.