Pitchers Who Should Increase Their Slider Usage

Patrick Corbin is the king of slider usage. On average he throws his slider 40% of the time. Why? Well, when you have a pitch that is so good why not throw it more? Like a lot more. It worked wonders for Patrick Corbin and his performance level. Here are three pitchers who could benefit from a pitch mix change like this.

Masahiro Tanaka is a very interesting case for the 2021 season. After a disappointing season in 2019, he bounced back in 2020 with a 3.56 ERA in 48 innings pitched. If we dig a layer below the ERA we find a 4.42 FIP, 4.19 xFIP, and 4.07 SIERA. A low four ERA isn’t bad but if Tanaka wants to stay in the mid three ERA range he needs to keep his current pitch mix trend moving. Check out his pitch mix in the last few years.

Tanaka has been using his slider more and more as the years have gone on. The main reason behind this is the split-finger not performing as well as it used to.

In order to continue his success, he needs to continue to go to the slider more. The split-finger is by no means a bad pitch. It’s still good but it’s just not the same. Overall his slider is fantastic, last season it produced a 42.6 O-Swing%, 21.5 SwStr%, and .225 xwOBA. Bringing that pitch up to 40% could very well keep him below the four ERA threshold.

Chad Kuhl eventually moved into the rotation for the Pirates last season. As a starter, he pitched 41.1 innings with a 4.57 ERA, 5.78 FIP, and 4.90 xFIP. What’s so interesting about Kuhl is his stuff is really good. In fact, if you use Ethan Moore’s Quality of Pitch (QOP) metric he is ranked up there with Mike Soroka and Kenta Maeda.

Kuhl can take a step forward if he caters more towards his breaking stuff, especially the slider. He mainly throws a sinker (42.1% usage) but it just flat out isn’t a good pitch. His command on it is terrible and it gets crushed. Actually crushed might be an understatement. Opposing hitters had a 186 wRC+, .309 ISO, and .448 wOBA against it. Those are some of the worst numbers I have ever seen for someone’s number one pitch.

When you move on to the slider that he throws 34.5% of the time the numbers look much better. Opposing hitters only had a 52 wRC+, .244 wOBA, and .058 ISO against it. He also was able to induce whiffs as it posted a 20.1 SwStr%, well above the league average of 17.1%. While he should probably throw it out of the zone more his slider doesn’t possess any flaws, so why not throw it 40% of the time?

Kuhl needs to dump the sinker or at least drop the usage to 30%. Relying on his slider and curveball could work wonders. The bad news is he hasn’t started to trend that way like Tanaka has, so until he shows us a pitch mix change he’s nothing but a streamer.

Did you know Jack Flaherty has arguably the best slider in baseball? It literally performs at all levels. Looking at contact quality, last season it produced a 0.0% dynamic hard-hit rate, tied for best in the league. Opposing hitters also only had an 82.7 exit velocity against it, that’s third-best in the league. Induces weak contact? Check. What about strikeout potential? His slider had a 26.2 SwStr% which was sixth in the league of all pitches. Oh yea and it was top 20 in the league in CSW. Just a fantastic pitch. But he only throws it 28.7% of the time.

While Flaherty has proven himself in the past his one flaw lies in his fastball. When he went on that crazy run in the second half of 2019 it was because his fastball was overperforming. Some believed the progress but in 2020 it was proven that his fastball is just about average.

His fastball isn’t as bad as it was in 2020 but it isn’t as good as it was in 2019 either. It probably looks more like his 2018 numbers. He threw this pitch 51% of the time and while yes it does set up his other pitches it would probably do him some good to tone it down. Unleash the slider more, use the best pitch you have more and success should follow.

Overall we have three interesting, different, and dynamic cases in this article. Of course throwing a pitch more is easier said than done. And of course, it’s hard to account for game plans and the types of hitters these pitchers face every day. The thing is when you look at a team like the Cleveland Indians who force their pitchers to throw their breaking stuff more they have so much success doing it and I wonder why other pitchers don’t follow suit. With these three pitchers it very well could pay dividends.