Strikeout Rate Risers - Starting Pitcher Breakouts for Fantasy Baseball

We are now halfway through the month of May and some interesting names have risen to the top of the strikeout leaderboards. If you don't follow my work already, I do daily strikeout projections for DFS and sports betting, so I am constantly looking at pitchers' strikeout rates and trying to gauge if they can hit their props in the right daily matchups. But the longer I dig into strikeout rates, the more I realize that a lot of different factors can really affect them, too.

When you glance at the league leaders in strikeout rates, Clayton Kershaw, Spencer Strider, Shane McClanahan, and Shohei Ohtani are names you expect to see. But we already knew they had great strikeout chops and this article is not about those pitchers.

Instead, I wanted to focus on the pitchers who are enjoying a big uptick in their strikeout rates and see if there's reason to believe that they can sustain their newfound success. I'll attempt to examine their advanced stats and take a look at which changes they may have made to their pitch mixes in an attempt to gauge just how legitimate or possibly fluky their improved strikeout rates might be!

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2023 Strikeout Risers

Let's establish the criteria for how I identified the players we are analyzing today. I'm looking for pitchers with above-average strikeout rates (league average is around 20-21%) who have improved their K% by at least 5% from last year and who have pitched at least 40 innings this season.

It's a really interesting collection of names here with pitchers of all experience levels. As you can see we had one major jump (Mitch Keller) and a bunch of guys who jumped 5-7%, which is still very substantial and potentially impactful.

What I intend to do here is break this group down into a few different tiers. Let's start with the studs were already very good at getting strikeouts, but have taken things to the next level.

From Good to Great - Strikeout Risers

Kevin Gausman - 34.2% K%

Gausman's K% actually jumped another half point to 34.7% after a 10-strikeout outing against the Yankees last night. He's now been dominant in six of his eight starts this season and he got blown up in the other two. So it's been feast or famine for Gausman this year, but mainly feast.

In fact, 15 of the 20 earned runs he has allowed on the season came in those two bad starts against Boston and Houston.

Gausman jumped out to a quick start last season, too, but then ended up regressing back to a 28% strikeout rate by the end of the 2022 season. So what's he doing differently so far this season?

He's also made it known that he's been experimenting with different velocities on his fastball. While his average fastball clocks in around 94 MPH, he has thrown it as low as 88 MPH and as high as 98 MPH.

Gausman's excellent control remains this year as he's walking just 4% of hitters in his second season in Toronto. His SwStr% is strong again this season at 15.6%, but is that high enough to sustain his 34% K%?

SwStr% to K% Translations

8-9% SwStr% ➡️17% K%
9-10% SwStr% ➡️18% K%
11-12% SwStr% ➡️20% K%
12-13% SwStr% ➡️23% K%
13-14% SwStr% ➡️25% K%
14-15% SwStr% ➡️26% K%
15-16% SwStr% ➡️28% K%
16-17% SwStr% ➡️33% K%

— Jon Anderson (@JonPgh) May 4, 2023

Jon collects more data than anyone I know and provided this useful chart recently that I think can be a helpful guide. It seems more likely that he's bound to be in the high 20s or low 30s based on this data, so we may in fact be at Gausman's peak right now.

However, I would expect him to continue to be really good (and elite pitchers who strike out a bunch of dudes without walking anyone don't exactly grow on trees) so I'm not sure that a market really exists for Gausman if you wanted to capitalize on a sell-high moment.

Just ride it out with Gausman, he's as good as his craft as he's ever been right now and he's making some minor tweaks that are getting big results.

Zac Gallen - 32.1% K%

Gallen has been a great story this year so far. He's the perfect example of how learning to pitch and use your arsenal of pitches is far more important than just having overwhelming velocity or a wipeout breaking pitch.

Gallen is sporting a career-high 14.5% SwStr% and 32.4% CSW% through his first nine starts. When trying to pinpoint what has pushed up into the elite strikeout range, it's actually really tough to connect the dots here and find just one cause.

It's likely a combination of little things. Like Gausman, Gallen has had absolute pinpoint control with a 3.7% BB%. That's a 3% drop from last year and is likely due, in part, to him getting ahead in the count early.

He's increased his first strike percentage by 4.7% (up to 69%, the league average is usually closer to 60%). Proponents of first strike percentage will point out that around 70% of all strikeouts start with a first-pitch strike while 70% of all walks start with a first-pitch ball.

But besides getting in front of hitters, Gallen has made a small tweak to his pitch mix. He's throwing his fastball (not overpowering at 93-94 MPH) less and his curveball (very effective with a 43% whiff rate). His changeup is excellent, too, with a 32.9% whiff rate of its own.

He really just throws his cutter for strikes and to change up speeds on hitters. He can throw the cutter anywhere from 85 MPH to 91 MPH and it helps bridge that velocity gap between his curveball and fastball.

Our SwStr% chart suggests that Gallen is more likely to be a 25-26% strikeout guy (as he has been) than a 30% or better pitcher and some regression is probably coming. However, we can't totally quantify the small changes he's made or the intangibles like the confidence that he has right now to throw all of his pitches for strikes in any count.

Pablo Lopez - 30% K%

Pablo is enjoying the best start to a season in his young career since coming to Minnesota this offseason. His new pitch arsenal has been pretty well-documented, including my esteemed colleague Eric Samulski here at RotoBaller. He ditched his cutter entirely and is now throwing the sweeper and changeup around 20% each to compliment his 95 MPH 4-seam fastball.

Pablo Lopez, 88mph Changeup and 84mph Sweeper, Overlay pic.twitter.com/CXppvPzfG7

— Rob Friedman (@PitchingNinja) April 12, 2023

The change and sweeper break in opposite directions and have really kept hitters off balance thus far. The sweeper is generating a lot of whiffs outside the zone and carries a 39% whiff rate overall, while his changeup continues to be really effective as an out pitch, too, with a 30% whiff rate of its own. He's getting hitters to swing at pitches outside the zone at a nearly 36% rate, which is 4% better than last year and represents a career-high.

With a solid 15.8% SwStr% so far, it's reasonable to think that he can continue to flirt with a 30% strikeout rate for the rest of the season.

Sonny Gray - 30.8% K%

Sonny Gray's story this year is a fun one as the 10-year veteran is off to the fastest start of his career. He's carrying a 1.39 ERA and a 1.08 WHIP and has seen his ground ball numbers improve back up to a 52% GB% as well. We are not here to talk about his run prevention, however impressive! We are here to talk strikeouts!

Gray has topped 30% in strikeout rate only once before in his career (2020 in Cincinnati) and checked in at only 24% last year, which was his first season in Minnesota. Since his first start when he struck out only one hitter, he's struck out six or more hitters in every start.

Gray's pitch mix chart offers us a fascinating look at how this veteran has continued to evolve his arsenal.

He's throwing six different pitches this season! Most notably he's increased his cutter and changeup usage while switching over from a more traditional slider to a harder-breaking sweeper. His sinker sits in the 92-94 MPH range but that's been fast enough to fool hitters since he's throwing such a variety of offspeed stuff.

The curveball and sweeper have been incredibly effective with 40% and 43% whiff rates, respectively. He has hitters guessing on every pitch and is hitting his spots on the inside and outside corners.

Sonny Gray, Filthy Two Seamers. 🌞 pic.twitter.com/8ybnyAFyMk

— Rob Friedman (@PitchingNinja) May 13, 2023

He's sitting at 13.5% for his swinging strike rate which is a major improvement over his 9.5% rate from last year. But that means he's also getting a decent number of called strikes, too. It's possible we are seeing him break into another tier of strikeout performance late in his career as Gausman did, but it's equally possible that he regresses here a bit and settles in around 26-27% for the rest of the year, too.

Young Guns Making Big K% Gains

Mitch Keller - 30.1% K%

No one is as happy as me to see the Pirates youngster take this jump and become a full-fledged ace pitcher. If you weren't sold on Keller over his first month of work, his last two starts should have left no doubt that he's on a major upward trajectory as he tossed a CGSO against the Rockies and followed that up with a 13-strikeout outing against a good Orioles team.

Mitch Keller, Ridiculous 83mph Sweeper. 😳

21 inches of Horizontal Break pic.twitter.com/ifHhgPC4OK

— Rob Friedman (@PitchingNinja) May 14, 2023

It turns out that adding a sweeper is all the rage for RHP this season and Keller added one last year, too, giving him yet another solid breaking pitch as he already had an excellent curveball, too.

His velocity jump happened last season and got our hopes up in Spring Training only to see him struggle again for the first half of the 2022 season. It was only in the second half of the year when he really started to lean on his sinker (which he throws just as hard - around 94-95 MPH) that he started to see real improvement.

He now throws five quality pitches (I'm not really counting his changeup here) and with the addition of his cutter, he now has something he can throw in to lefties, too.

Added a Called Strike% vs. Swinging Strike% scatter plot to the dashboard this morning

Shows how every pitcher is getting to their current CSW%

SwStr% guys: Strider, Shane, Greene, Castillo, Kershaw, German

Called Strike guys: Hill, Keller, Singer, Webb, Eflin pic.twitter.com/xQJgP73sj8

— Jon Anderson (@JonPgh) May 15, 2023

The real concern here would be that he's doing this with only an 11% SwStr% and all these called strikes aren't sustainable. His CSW% of 31% means he's getting 20% of his strikes and that's a testament to how well he's commanding his pitches in addition to the variety of different movements on his pitches.

The biggest leap means he's probably also the most likely to have some course correction here. But even if he ends up in the 25-26% K-range you're still looking at a major breakout for a guy who was nearly labeled a bust and who I drafted in the last round or two of most of my drafts this Spring (I'm either super sharp or just a major Pirates homer).

Logan Gilbert - 29.5% K%

Gilbert has taken a big jump here in his third full season as a starter. His K% actually dipped quite a bit last year from 25% in his rookie campaign to 22.7% as his SwStr% and CSW% also decreased a bit.

This year his SwStr% is exactly the same, but he's up 3% on his CSW%. The walks are down under 5% which is fantastic and his velocity is actually down about 1.5 MPH on his fastball while his slider velocity went up over 1 MPH.

So it's a mixed bag of results here, but one noticeable change in his arsenal is the introduction of a splitter as an offspeed pitch instead of a changeup. He's throwing the splitter about 10% of the time and getting some great results with it (.135 xWOBA, 31% whiff rate).

Logan Gilbert, Disgusting 86mph Splitter...and Sword. ⚔️ pic.twitter.com/MjnSMyNChC

— Rob Friedman (@PitchingNinja) April 19, 2023

Like Keller, I am a bit skeptical that he can keep this up with a 12% swinging strike rate, but it's clear that he's very confident in what he's throwing right now and I think he's poised for a big year. I think we see him regress a bit to the 25% range, which is fine and right around where he was when he broke into the bigs back in 2021.

MacKenzie Gore - 28.8% K%

This one is tough to figure out and even my buddy Samulski, the pitch whisperer, had a hard time honing in on how Gore's new curveball is getting such good results. You can read more of his take on it here, but the basic takeaway is that he's throwing his curveball now at 83-84 MPH instead of 80 MPH and he's seen a big bump in the whiff rate on it from 31% last year to 41% this year.

MacKenzie Gore, Dirty 84mph Curveball...

9th K. pic.twitter.com/R6iJAIARgV

— Rob Friedman (@PitchingNinja) April 27, 2023

Gore has seen a nice bump in his SwStr% from 11.2% last year to 13.7% and his groundball rate has really improved from 40% to 52% as well as he's doing a much better job of keeping the ball down in the zone. The walks are still a concern as his BB% is still right around 12%, but he's clearly missing bats more often and pitching deeper into games as a result of the improved contact metrics.

Some regression can be expected here, too, but like Keller - you probably bought into Gore cheaply this year so there's no reason not to keep riding him and reap the rewards of his stellar production so far.

K% Risers From the Teens to the Mid-20s

Just some quick hitters here on our final three guys on the list.

Domingo German - 26.3% K%

It's a return to form for these first few guys as both had flashed solid K potential before. We have to go back to 2018-2019 to find a 26% K% for German and he's battled back from some injuries to get where he is now.

His pitch mix is pretty similar to last year in that he's throwing the same four pitches (4-seam, sinker, curveball, changeup), but he's throwing his best pitch (the curveball) more often (40% of the time) and his worst pitch less often (down from 12% to around 10% of the time).

A healthy 15.8% SwStr% suggests that his current rate of K production is sustainable. It's really a matter of run prevention with him as he's still a bit HR-prone.

Eduardo Rodriguez - 24.7% K%

E-Rod starting off the year a bit rocky, but has looked fantastic over the last month. He's seen his strikeouts return to right around where they were during his time in Boston and he's sporting an impressive 1.57 ERA and 0.79 WHIP while doing it.

The walks are down to 5% and his SwStr% has rebounded to a healthy 11% after dropping to just 8.4% last season.

The only real thing I notice about his pitch mix is the decrease in sinker usage. That's a good thing for strikeouts as his sinker has only an 8% whiff rate. He's throwing more four-seamers and changeups (his best pitch) as a result and getting more whiffs.

I don't think this level of run prevention is sustainable, but a solid 24-25% strikeout rate certainly seems to be for E-Rod based on his peripherals.

JP Sears - 24.6% K%

Who said only righties can have fun with sweepers? Oakland's young left-hander added one to his arsenal this year and gave himself a quality third pitch as he was basically a two-pitch pitcher last year throwing a four-seamer and changeup only.

JP Sears with a career-best 11 strikeouts against the Rangers on SAT, but probably can't expect that type of ceiling on the regular.

✅More whiffs on the 4-seamer
✅More whiffs on sweeper/slider, especially vs RHH
😬Luck factors
🧐Fewer GB (on the slider), & more FB pic.twitter.com/SZyIA1LxRc

— Corbin (@corbin_young21) April 22, 2023

The sweeper has a decent whiff rate of 24.6% but is also getting hit to the tune of a .444 xSLG at the same time. His fastball and changeup are better pitches for whiffs but are also getting hit hard, too. His ERA is sitting at 5.55 with a 5.01 xFIP. He's giving up a ton of fly balls and barrels and is one of the only guys on our list who has been really bad at run prevention while still being good at getting strikeouts.

His SwStr% right now is 14.1% up from only 9% last year and that has to be a good thing. But he still feels like a young pitcher who is trying to figure things out and because of that, there are going to be some extreme lows with the highs. He's rosterable in even shallow leagues right now, but he's also a guy I would consider benching when he runs into a tough matchup.

He reminds me a bit of Bruce Zimmermann last year and I would expect him to probably settle into the 22-24% range here over the course of the rest of the season.

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