Using Data Analysis To Spot Strikeout Risers

Jon Anderson explains how to use sabermetrics to find starting pitcher strikeout risers for 2021 fantasy baseball. These SP could be breakout performers.

The key to winning a fantasy league is to spot things that are to come before they happen. This is what we try to do here every day at RotoBaller. As the years have gone by, more data about the game has been made available to us, and we can use that data to make better predictions and projections.

For this post, I did three different data analysis projects with the intention of looking for things that predict strikeouts. The object is to find pitchers that are excelling at strikeout predictors without really excelling at strikeouts themselves.

While this isn't a perfect exercise, and we will never be perfectly successful at seeing improvements before they happen, I think the players I talk about in the following have a better than average chance of seeing their strikeouts tick up this year. Here we go!

Count Analysis

You can't get a strikeout unless you've already gotten to a two-strike count. That means a pre-requisite for a high strikeout rate is getting yourself into a lot of two-strike counts. I took a look at all strikeouts over the last two seasons and see how they broke down by what the count was when the strikeout occurred. Here's the breakdown:

This does not mean that 1-2 is actually a more advantageous count to be in than 0-2, since 1-2 often follows right after an 0-2 waste pitch that goes unchased. The 1-2 count is just the sweet spot for strikeout pitches being most effective.

Let's look at some leaderboards from 2019-2020. First, here are the top 10 starters (2,000 pitch minimum) by what percent of their pitches have been thrown in two-strike counts:

% Of Pitches Thrown With Two Strikes

% Of Pitches Thrown in 0-2 Count

So for the most part you have high strikeout pitchers showing up here already. That makes sense since you get strikes one and two the same way you get strike three. Some notable names on the list that haven't found themselves striking out a ton of hitters over the last two seasons are detailed below.

Chris Paddack: He's done nothing but throw strikes since he entered the league. He sits second in this study in getting to 0-2 counts, and yet his overall strikeout rate sits behind the rest of the names surrounding him at "just" 26%. The reason for this surely has to do with his pitch mix, Paddack throws a four-seamer 58% of the time in two-strike counts. As we will see in the next section of this post, four-seamers are one of the worst pitches at generating whiffs. Most of the rest of his two-strike pitches are changeups, which is a much better pitch at getting the whiff, but is still not nearly as good as some of the sliders and curveballs other pitchers feature. Paddack is still a young pitcher and is more than capable of adding to his pitch distribution, and if he ups his curveball usage and/or adds another pitch, we could really see his strikeout rate come up substantially.

Nathan Eovaldi: It's the same story here. Eovaldi gets into two-strike counts at the third-highest rate in the league, but his overall strikeout rate is lagging behind at 24.4%. The problem with Eovaldi is that 65% of his pitches in two-strike counts have been four-seamers and cutters, two pitches that do not get a lot of whiffs. He does throw a curveball as well at an 18% clip in two-strike counts. He also has dabbled with a slider (2%) and a splitter (15%), so if he would increase the usage of those pitches in two-strike counts he would probably get more strikeouts - keep an eye on Eovaldi this year.

Madison Bumgarner: It has been a rough couple of years for Bumgarner, but one thing he has kept doing is getting ahead of hitters. He has not taken advantage of this in the last two seasons with a pretty weak 22.7% strikeout rate overall. He too has been pretty reliant on the fastball while ahead in the count, throwing a cutter (36%) and a four-seamer (38%) the majority of the time. His curveball is not what it used to be, or at least it has not been in the last two seasons, and that has cost him some strikeouts. If Bum can get a little bit of his "stuff" back this year, he could see his strikeout rate come back up into the mid-twenties rather than being around 22%.

Joe Musgrove: The new Padre has thrown a ton of strikes over the last two years, throwing 8.3% of his pitches out of an 0-2 count. His strikeout rate over the sample is just 24%, but that did balloon to 33% in his limited 39.2 innings in 2020. This came as the result of a pitch change, where he threw fewer four-seamers and more sliders and curveballs. That makes the strikeout rate increase much more believable, and if he keeps that up with his new team I absolutely would expect a strikeout rate in the high-twenties from Musgrove in 2021.

Pitch Mix

Here are the swinging-strike rates of each of the six most-used pitches in the game over the last two seasons:

Here is how often each pitch is thrown both overall and in two-strike counts:

and here's the breakdown for what percent of the time each pitch gets a strikeout when it is thrown on a two-strike count:

So what we see here is that pitchers reduce fastball (four-seamers and sinkers) usage and increase breaking ball usage (sliders +3.6%, curveballs +1.5%). And that is for good reason, as sliders and curveballs indeed generate more strikeouts when thrown on two-strike counts, and the fastballs come in last in that metric.

What we are interested in now is to look at the leaderboard in terms of which pitchers throw the most sliders and curveballs in their two-strike counts. Here are those leaders, the percentage you see below is what percent of their total two-strike pitches are sliders or curveballs.

Interesting names from this list:

Jakob Junis: The Royals righty has an underwhelming strikeout rate over the last two seasons at 21%, but he does throw a ton of sliders in advantageous counts at 55% usage. The slider also has a really high whiff rate at 26.3%, it's a strong pitch for him. What may be holding him back is that he doesn't get himself ahead in the count nearly as much as the high strikeout pitchers. He's thrown just 5.2% of his pitches from an 0-2 count the last two seasons. His first strike rate is right at the league average at 61%. If he can get himself into two-strike counts more often, he could see his strikeout rate balloon quite a bit. Possibly helping this is his introduction of a cutter that he is working on this spring. If he would substitute some cutters for four-seamers, he could generate more swinging-strikes overall and find himself in strikeout counts more often.

Max Fried: I don't think we can really count on Fried to be anything different than what he has been, but it is interesting that he shows up here. In two-strike counts, Fried throws a slider 26% of the time and a curveball 30% of the time. He doesn't get himself into strikeout counts at a really high rate either, and a lot of is intentional. Fried throws lots of curveballs in the strike zone with the hope of generating ground-balls, and he has been wildly successful with that strategy so I don't expect a change. If luck does break a certain way and he gets deeper into some counts this year, he does seem to have a higher strikeout ceiling than a lot of people think with how often he throws the breakers with two strikes on a hitter.

Swinging Strike Rates By Count

I was curious to see how swinging-strike rates breakdown by count. It turns out that, over the last two years, 71% of strikeouts have come on swinging-strikes (compared to strikeouts looking). Because of this, I'm going to focus on swinging-strike rates rather than CSW (called strike plus whiff rates). What I wanted to see is which pitchers have lower swinging-strike rates in two-strike counts as compared to their total. Here are the biggest differentials:

You can see that only LeBlanc, Holland, and E-Rod have swinging-strike rates lower in two-strike counts compared to their average. This no doubt has to do with the fact that hitters are much more likely to swing with two strikes on them. The league average overall swinging-strike rate is about 11.1%, in two-strike counts that jumps up to 13.7%. These pitchers have all been pretty unlucky in getting whiffs when it matters most, and I would expect this to be a category where you see regression to the mean.

That means it's reasonable to expect a few more strikeouts out of the guys on this list. The names interesting for fantasy there are E-Rod, Means, Eovaldi, Woodruff, and Plesac. In the case of Rodriguez and Woodruff, these are guys that were already getting a good amount of strikeouts. As for Means, Eovaldi (again), and Plesac, there seems to be room for growth.

Conclusion

This analysis is much better for teaching a method rather than pointing to specific players. If you are looking for pitchers that you can expect a lot of strikeouts from, here are the tips:

1. Look for guys that get ahead in counts. The most common metric available on this is first strike rate, which is the percent of a pitcher's first pitch that they get a strike with. The problem with this is that it's actually not correlated to strikeout rate. The league leaders in first-strike rate are no more likely to have high strikeout rates than anybody else. Getting to 0-2 or 1-2 is much more correlated with strikeout rate than just going for 0-1.
2. Look for high slider and curveball usage. 70% of strikeouts are had by the whiff, and these two pitches are far and away the best at generating whiffs. If a guy is throwing a ton of fastballs in two-strike counts, he's going to have more trouble punching batters out.
3. Swinging-strike rate is king. That is the category that is most correlated with strikeout rate. This metric is available everywhere, so keep an eye out for pitchers posting high swinging-strike rates early in the season.

The guys that stood out to me here most are Joe Musgrove, Nathan Eovaldi, Chris Paddack, and John Means.

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