Identifying Elite Fantasy Baseball Pitchers for Drafts - Plate Discipline Metrics Studs

One of the reasons I love fantasy baseball so much is that it allows me to crunch numbers and data more than other sports. Baseball is such a stat-driven sport and there's no shortage of statistics to examine, especially now in the days of Statcast, PitchFX, and Stuff+.

For my final deep stat dive of the Spring, I wanted to look for starting pitchers who posted really good numbers in plate discipline metrics. Part of that research led to an examination of how well certain statistics correlated with pitcher performance in what matters the most for our fantasy leagues - ERA, WHIP, and strikeouts.

I offer you the findings of my research here and, of course, will highlight some of my starting pitcher targets in the process!

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Research Methodology and Process

The statistics that I examined in this process were mainly plate discipline stats (SwStr%, O-Swing%, Z-Contact%, F-Strike%) with CSW% and Pitching+ also included as potential "overall" metrics that measure more than variable and could be useful singular stand-alone metrics if the correlation proved to be significant. I'll go into more detail about each metric later in each section.

All the data used in this article is derived from the population of starting pitchers who threw at least 80 innings last season. That ended up being about 140 pitchers.

I set out to see if I could find some advanced statistics that showed a strong correlation with starting pitchers' strikeout rates, ERA, or WHIP.

If I located some of those statistics, could I then use them to hone in on starting pitchers who were demonstrating those skills at a high-rate as targets for this coming fantasy baseball season?

I ended up finding the correlational coefficients for many different statistical pairings. Some of these stats showed very little correlation, while others were highly correlated, and I'll spend more time discussing those and the pitchers who "popped" in certain categories as a result of my research.

Statistical Correlations For Advanced Statistics

The first thing I did was run the correlations for each of the six selected statistics with both ERA and SIERA. Not surprisingly, the correlation for each statistic was stronger with SIERA than ERA, proving again what we already knew: that ERA is luck-based rather than skill-based.

Of course, ERA is the stat that counts in our leagues, not SIERA, but we are trying to predict future ERA and SIERA simply does a much better job of that than a pitcher's current ERA.

As a refresher, correlational coefficients range from -1.0 to 1.0 with stronger positive correlations being closer to 1.0 and stronger negative correlations being closer to -1.0.

A positive correlation simply means that as one number goes up, the other paired number does, too. The only statistics in this set that are positively correlated are ERA and SIERA with Z-Contact%, which logically makes sense that a pitcher's SIERA would go up if they allow MORE contact on pitchers in the strike zone.

The number we usually seek to suggest even a moderate relationship is 0.4 (or -0.4). A coefficient of 0.7 (or -0.7) or higher would suggest a strong relationship. Our three qualifiers for strong correlation were SIERA and Pitching+ (0.77), SIERA and SwStr% (0.73), and SIERA and CSW% (0.80).

The correlations between SIERA and O-Swing% and Z-Contact% were moderate and high enough to be noteworthy, more on those relationships in the next sections.

The one statistic that didn't show a very strong relationship with SIERA or ERA was F-Strike%, which measures how often a pitcher throws a first-pitch strike to start an at-bat. While it's important for some pitchers to pitch ahead in the count, others (like Dylan Cease or Cole Ragans, for example) have such overpowering stuff that it doesn't phase them.

But I also ran the correlations for F-Strike with BB%, WHIP, and K%. The weakest was K% at only 0.10, but the relationship with BB% was pretty significant at -0.63. So, in other words, getting ahead in the count is far less important to striking out a hitter than it is to NOT walking him.

And since walks are such a big component of a pitcher's WHIP, the -0.34 mild correlation between WHIP and F-Strike makes a lot of sense. Low WHIP pitchers are almost always guys with good control, and the F-Strike percentage appears to be a leading indicator of that success.

Here are some quick definitions of the other statistics.

SwStr% is the total number of swings and misses as a percentage of a pitcher's total pitches. The league average is usually around 10-11%.

CSW% is the total number of swinging strikes AND called strikes as a percentage of a pitcher's total pitches. The league average is around 27%.

Pitching+ is a metric that attempts to gauge the effectiveness of a pitcher based on the physical characteristics, location, and situation of every pitcher, including the count and hitter handedness. The average rating is 100.

The two plate discipline metrics I was the most interested in testing out were O-Swing% and Z-Contact%. O-Swing% measures how often hitters swing at pitches outside the strike zone. It's represented in the data as a percentage of the total number of pitches thrown outside the zone. The average from the data set that I used was 32% last season.

Z-Contact% is the opposite statistic as it measures how often hitters make contact with pitches thrown inside the zone, represented as a percentage of the total number of pitches thrown in the zone. Last year's average among the qualified starters was 86%.

Joe Ryan: First Strike Stud

Not too many guys can sport a WHIP under 1.0, but Ryan had a 0.99 WHIP last season and sports a career mark of 1.07. His F-Strike% of 70.4% was the fourth-best among qualified starters behind only Bryan Woo, Miles Mikolas, and Brandon Pfaadt.

Ryan threw only 135 frames last year, which is why you can still get him at a discount around picks 100-110. He's one of the few elite control pitchers who is also a pretty good strikeout pitcher (27% last year, 29% in 2023), and he's already whiffed 13 hitters in his first eight frames this Spring.

Want a cheaper version of Ryan? Check out Brandon Pfaadt's numbers when compared to Ryan's.

I've already written a lot of words about Pfaadt as a post-hype breakout here, but I can't help but give him another plug where I can.

Shota Imanaga: SwStr% Legend

There's a good chance that by the time you read this, Imanaga has already made his debut against the Dodgers in Tokyo. I wouldn't read too much into that start, but I am reading into the stellar across-the-board numbers he posted last season in his rookie campaign.

Imanaga had a 29% K% his last season in the NPB and he proved that he could strike out major league hitters nearly as often with a 25% in 2024. He gets it done even without above-average "stuff" as he had only a 98 Stuff+ rating last year, but a very solid 106 Pitching+ rating.

He's getting a lot of swings and misses outside the zone with his splitter, which he threw around 30% of the time. His four-seam fastball clocks in only around 92 mph, but he has a very good induced vertical break on it at an average of 18.3 inches.

The rising action of the fastball, paired with the splitter's downward plane, gives hitters fits. Imanaga's ability to locate both the fastball and splitter in any count makes him incredibly effective.

We should recognize that we aren't dealing with a second-year pitcher here who could regress after a good first season. We are looking at a 31-year-old veteran who is a master at his craft. I'm happy to draft him around his current ADP of 65, and I expect him to have another very productive season in Chicago.

Sanchez and Schwelly: More O-Swing Stalwarts

There are two pitchers that I am trying not to leave drafts without this season: Spencer Schwellenbach and Cristopher Sanchez. These two probably don't qualify as "sleepers" anymore, especially Schwelly who is going inside the top 100 now (and as high as the 60-70 range). I'm happy to "reach" for him around there, as I think he could take a Tarik Skubal/Cole Ragans type of leap this season.

I've been getting sniped on Sanchez later in drafts because he's simply pitching too darn well this Spring and the secret on him is out. He's throwing 97 mph on his heater (up at least two ticks on the radar gun) and still featuring a dynamite changeup that falls off the table. You better plan to take him a few rounds ahead of ADP (167) if you're in a competitive league - let's just say that.

Of all the pitchers in my sample, Sanchez had the best O-Swing% rate, thanks to the aforementioned changeup. The change had a Stuff+ rating of 118, which was the third-highest-rated changeup behind only Skubal and Michael Wacha.

The changeup drops 37 inches with 18 inches of arm-side run. Right-handed hitters flail at it helplessly as it moves down and away from them, ultimately dying in the dirt. No matter what metric you look at, it was one of the best pitches in baseball. The whiff rate was 34.8%, and opposing hitters managed to have only a .177 batting average against it. If he can sustain the big gain on the radar gun with the heater, it's only going to make an even bigger contrast with the changeup that averages 85 mph.

This is a profile of an emerging ace, and I'm expecting a huge breakthrough for Sanchez. He could end up being the No. 2 starter behind Zack Wheeler at some point this season.

And now, to keep driving the Schwellenbach hype train! No matter what stat you dig into, you're going to like what you find with Schwelly.

Not many 24-year-olds throw six pitches and throw them all well. This is one of the most versatile pitch mixes you will see, and he can throw all six for strikes while eliciting a lot of chases from hitters with his slider (28% whiff), curveball (41% whiff), and splitter (46% whiff) out of the zone.

The distribution of his pitches in terms of velocity is pretty impressive, too, as hitters have to be prepared for high-90s heat, high-70s breaking pitches, and everything in between.

I'm all in on Schwellenbach for a huge sophomore season and the sky is quite literally the limit with an arsenal that is this varied and top-notch control. He blew through the minors quicker than most pitchers for a reason - he's demonstrated an elevated knowledge of how to pitch and isn't reliant just on velocity or one main offspeed pitch.

Bailey Ober: Best of Both Worlds

You can snag Ober around pick 92 in drafts right now, but I'm aggressively targeting him about a round earlier. Ober is not a youngster at age 29 but is entering his fifth season in the majors after going 12-9 last year with a 3.98 ERA and 1.00 WHIP across 31 starts.

Ober did a bit of a Jekyll-and-Hyde act in 2024, allowing five or more earned runs in five starts but also holding teams to three earned runs or fewer in 21 starts. As a fly-ball pitcher, he was home-run prone, allowing 27 big flies. His home-run issues led to some of those blow-up starts, but he was so good in his other starts that I'm intrigued as to whether or not he can be more consistent going forward.

The plate discipline metrics all look really good and I included the rankings so you could see just how good compared to his peers. He set a career-high in K% at nearly 27% as he ditched his curveball for a slider, giving him two very differently shaped breaking pitches between his slider and sweeper.

His changeup is arguably his best pitch, as he sported a 39.4% whiff rate on it last year with a .164 xBA. It averaged 17 inches of arm-side run, and Ober paired it with the sweeper (12 inches of glove-side run) to own both sides of the plate.

His offspeed stuff is so good that he's able to get by with just average velocity (92 mph) on his fastball. The underlying metrics here suggest that Ober has command of a very solid arsenal that he can continue to deploy to get big-time results. If he cuts down on those bad starts, we are looking at a pitcher who is ready to take the next step and perhaps become the ace of a very good Minnesota pitching staff.

Other Pitchers Who Were Average or Better in All Six Categories

• Brandon Pfaadt
• Tarik Skubal
• Logan Gilbert
• Yu Darvish
• Ryan Pepiot
• Nathan Eovaldi
• Blake Snell
• Garrett Crochet
• Zack Wheeler
• Chris Sale
• Grayson Rodriguez
• Gerrit Cole

If you have been reading my other starting pitcher content, you'll know that more than a few of my other favorites are on this list, too! Gerrit Cole is not an option, and Grayson Rodriguez is hurt. Chris Sale is an aging injury risk, but the rest of these guys are firmly on my radar this season.

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