High Called Strike Rate, Low Swinging Strike Rate

What’s the first thing you do when you get a new spreadsheet? My answer; sort ascending, sort descending. That’s what I did on the 2021 pitching leaderboards. I looked at the plate discipline metrics for qualified pitchers and sorted the sheet by descending swinging-strike rate (SwStr%). The names I saw were not surprising. Corbin Burnes leads the group at 16.6%. He’s followed by Max Scherzer (15.9%) and Robbie Ray (15.5%). José Berríos is not in the top 30. In fact, when you sort the same list by ascending swinging-strike rate, he’s in the top 10, meaning he had one of the lowest swinging strike rates in the league (9.9% to be specific). The lowest swinging strike getters in the league this year were Adam Wainwright (8.1%), Chris Flexen 플렉센 (8.6%), and Dallas Keuchel (8.7%).

Now, do the same sorting exercise on called-strike rate (CStr%) and you’ll find the opposite pattern. José Berríos has the third-best called-strike rate (19.2%) among 2021 qualified starters behind Adam Wainwright at first (21.6%) and Lance McCullers Jr. (19.8%) at second. Does that seem strange? What qualities do pitchers who get a lot of called strikes and very little swinging-strikes have? To answer that question, let’s start by looking at starters with at least 100 IP in 2021 who have the largest differentials between their called-strike rate and their swinging-strike rate:

Is that good? Well, you certainly would rather have a guy who can do both. If we look at pitchers from the same group of 2021 qualified starters who have very little difference between the two rates we would see guys like Robbie Ray (15.5% SwStr%, 14.1% CStr%) and Lucas Giolito (15.3 SwStr%, 14.5 CStr%) and Clayton Kershaw (16.6 SwStr%, 16.0% CStr%). Doing both is good, but there’s more than one way to add strikes. José Berríos likes to do it with the curveball like this…

and with the sinker, like this…

Pretty incredible-looking stuff. One goes this-a-way and one goes that-a-way. But, why no takers? Is the late break fooling batters? Why is it that when they do swing, they make contact? Berríos isn’t missing bats, his contact rate was higher than the league average of 76.9%, as batters made contact on his pitches 78.9% of the time. Does a high called-strike rate correlate with anything in particular?

Called strike rate has a large negative correlation with the zone swing rate. Duh. It has some correlation with CSW, Alex Fast’s new metric that encompasses both called strikes and whiffs. But, none of this really pops off the page. If we look back at the pitchers in the first table, we can start to develop some commonalities amongst the pitchers on the list. Many of them have a positive PVal on their curveballs (Wainwright, Espino, Hill, Freeland, Berríos) or a positive PVal on their changeup (Gonzalez, Matz, Lopez, Ryu) and some have both.

Is called strike rate related to the value of a breaking pitch? Maybe. If you can throw curveballs and changeups in the zone that fool hitters, you’re going to bump up your called strike rate. But, if you are doing it more and more often, hitters are likely to pick up on that and start taking hacks. Some pitchers might get hit pretty hard, others may be able to limit contact, or perhaps, limit quality contact. If we refocus our attention on 2021’s qualified starting pitchers and we compare Hyun-Jin Ryu and José Berríos, we see that these two pitchers finished the year in a similar fashion.

Berrios – 192 IP, 204 K, 3.52 ERA, 1.06 WHIP, 3.47 FIP

Ryu       – 169 IP, 143 K, 4.37 ERA, 1.22 WHIP, 4.02 FIP

From those lines, Berríos looks much better. But, looking at some of the underlying statistics we see very little difference between the two:

Ryu       – 29.9 Hard%, 35.1 O-Swing%, 71.9 O-Contact%, 85.5 Z-Contact%, 41.1 Zone%, 18.8 CStr%

Berrios – 32.5 Hard%,  34   O-Swing%, 64.1 O-Contact%, 85.6 Z-Contact%,  51  Zone%,  19.2 CStr%

The only telling difference here is that hitters made more contact out of the zone on Ryu than they did Berríos. But, Ryu put the ball in the zone less often. Many fantasy managers may be wondering what happened to Ryu in 2021 and the key is in his changeup. He just didn’t have it. In 2020, Ryu’s changeup PVal was excellent at 7.0. In 2021, it sunk down to 0.2. In 2020, Berríos changeup was valued at 1.1, and in 2021 it soared up to 4.2. These two pitches went in opposite directions. When Ryu was trying to place a good changeup in the zone, he missed or gave up contact. Berríos on the other hand was doing this:

Getting to the point now, if you’re going to be a pitcher who lives in the zone, you have to have good stuff. Does that mean high CStr% pitchers with good stuff should be valued a little higher this offseason? Let’s look at how the top five CStr% starting pitchers (qualified) finished from a fantasy perspective in 2021:

Adam Wainwright – 25th K, 10th WHIP, 11th ERA, 2nd W

Lance McCullers, Jr. – 23rd K, 24th WHIP, 12th ERA, 14th W

José Berríos – 14th K, 12th WHIP, 20th ERA, 20th W

Hyun-Jin Ryu – 31st K, 26th WHIP, 32nd ERA, 11th W

Joe Musgrove – 15th K, 14th WHIP, 14th ERA, 23rd W

None of these pitchers finished the season at the top of their class, but they all did pretty well. When I first started writing this I thought I was going to focus on just Berríos. I had him rostered in one of my Ottoneu leagues and he was awesome. He scored the 12th highest in FanGraphs points among all starters! That’s a little different in a points league but still really great. He also accumulated 192 IP. But, according to Fantasy Pros ADP, he was the 24th pitcher off the board in most leagues with an average ADP of 78. If you were valuing a pitchers’ ability to get called strikes pre 2021, then you likely rostered a few of these pitchers and hopefully, you did well.

As you prep for 2022, you may be able to gain an edge using CStr%. But first, let’s make sure it’s repeatable.

While the data is limited and the 2021/2019 (I removed 2020, maybe you can guess why…) comparison shows a decrease in r-squared, I still like what I see. As fantasy baseball writers and analysts will soon begin making their top 100 lists, I’m going to be looking for a cluster of pitchers in the 20’s and 30’s that have displayed the ability to put good pitches in the zone for strikes. Hopefully, none of my league mates read this.