Fastball Foundations: Starters Dominating with their Primary Fastball
A trip through fastball strike rates to see which pitchers are having the most success with their primary heater.
I have been watching pitcher data quite closely ever since this blog began, and one thing I’ve noticed is that it’s pretty clear that one of the most important things in locating a reliable starting pitcher for your fantasy team would be finding a guy who can get strikes at a high rate with their fastball. Time and time again we see young pitchers come up and have short-term success by throwing a bunch of breaking balls at hitters, but it never seems to last.
Think of all of the best pitchers in recent history, you will have a tough time coming up with a guy that has had multi-year constant success in the Majors without having a very good fastball.
Velocity helps, clearly, but you can make it work without it. That’s why today I’m going to be focused on Strike Rates. A reminder:
Strike% = (Called Strikes + Whiffs + Foul Balls) / Total Pitches Thrown
The goal of almost every pitch thrown is to earn a strike. Plenty of balls put in play work out fine for the pitcher, but the ideal general outcome is to earn a strike.
To set our standards, here’s a look at the pitch type benchmarks table from my main MLB dashboard:
Four-seamers earn the highest overall Strike% at 49%. They are the easiest pitch to command and you’re typically trying to throw it in the strike zone, unlike a slider where you might want it to look like a strike but then end up further away from where the bat cannot reach. Since the four-seamer is two points above the sinker and the cutter, we have to account for that when comparing these different types. So let’s get into it, we’re looking at the league’s highest Strike% on each fastball type, and then we’ll use those results as a launching point to talk about pitchers in detail.
I should at least attempt to prove that this matters. And while no single pitcher metric, especially not a single pitch level, will tell anywhere near the full story, we do see a bit of signal between fastball strike rates and WHIP:
Less so with ERA, but it’s far from a non-relationship:
Here is the data behind those plots if you want it. It uses qualified pitchers (at least 100 innings and at least 500 four-seamers thrown) from 2021-2023.
The average ERA for pitchers with a four-seam Strike% above 50% is 3.74, the average for guys with a Strike% below 50% is 4.33, a big difference.
For WHIP it’s 1.17 vs. 1.32, another big difference. Earning strikes with your primary fastball is really important and sets you up for success in the box score.
Four-Seamers
At the tip-top we have four names that we expected to see here, guys we don’t really need to talk about in this piece.
George Kirby - 59% Strike%
Kevin Gausman - 58% Strike%
Zack Wheeler - 58% Strike%
Pablo Lopez - 57% Strike%
All four of these guys were drafted in the top 10 at the position, and overall they’ve earned that. Kirby and Gausman have had a few iffy outings but overall strong numbers, and you can feel good about their continued dominance given how good these fastballs have continued to be.
There are some more interesting names in the next cluster:
Luis Severino - 57% Strike%
Mitch Keller - 56% Strike%
Jared Jones - 55% Strike%
Joe Ryan - 55% Strike%
Chris Paddack - 55% Strike%
MacKenzie Gore - 54% Strike%
Luis Severino hasn’t been all that great this year, but it’s been an improvement from the really bad 2023 season, and it’s good to see him here with the 57% Strike%.
He also has a very high 13.7% SwStr% on the four-seamer, and the pitch is averaging 95.9mph. Good stuff there, although he hasn’t really shown a fantastic secondary weapon, he doesn’t have a single non-fastball above the league average in Strike%. So I can’t say that Severino is likely to be great moving forward, but the solid base with the fastball (and the presence of a sinker and cutter as well) raise his floor considerably.
I was really surprised to see Mitch Keller here.
He’s had two really great starts in a row now and the fastball has earned a ton of strikes (mostly called strikes or fouls with just a 12.7% SwStr%). The way Keller has been getting it done the last two seasons is with command and variation. He throws 33% four-seamers, 23% sinkers, 22% cutters, 14% sweepers, 7% curveballs, and then a changeup or two every outing. He’s never had over-powering stuff, but 94.4 on the fastball is good enough when you can command it and tunnel it with other pitches. Solid floor starter here.
You already know about Jared Jones so we can skip over him. His four-seamer’s 20.4% SwStr% leads the league by more than two full points, which is just crazy.
Joe Ryan has also been doing this ever since getting into the Majors. It’s a slower four-seamer at 93.6mph, but the command and the deception are so good that he gets it done very single here in this regard, and that gives him a very nice floor (we’re developing a theme here about SPs and their floors).
Chris Paddack is the most surprising name on the list. He had a very nice 2019 season, but ever since then his fastballs were a real problem. Pitch values (from FanGraphs) on his fastball since 2020:
2020: -9.9
2021: -3.8
2022: +2.9
2023: -0.5
2024: +1.9
So this is just the second time he’s been positive since 2019. It’s a small sample here as he’s thrown just 263 pitches (the threshold for this post was 250, by the way), but so far - so good. A 14.8% SwStr% with that 55% Strike% and a really nice 28% Ball% and .272 xwOBA. Things still have plenty of time to go south, and it will be really interesting to see how he fares tonight against the Yankees. If these gains are for real, Paddack could end up having a really nice season given his strong changeup and also having the slider and curveball in the quiver.
As for MacKenzie Gore, he’s always had a good fastball in terms of velocity, but the command has long been an issue for him. This year, he’s been throwing it where he wants with that high 54% Strike% and a 32% Ball% which also beats the league-average by two points (a significant amount). More surprisingly is that he has yet to give up a home run on the pitch, which was a massive problem for him last year. Now, that probably means he’s been lucky and some home run regression is likely coming - but it’s also a probable sign of legitimate improvement in the command.
Next group:
Garrett Crochet - 54% Strike%
Chris Sale - 54% Strike%
Hunter Greene - 54% Strike%
Hunter Brown - 54% Strike%
Yusei Kikuchi - 54% Strike%
Cole Ragans - 54% Strike%
Jack Flaherty - 54% Strike%
Bryce Miller - 54% Strike%
Tyler Glasnow - 53% Strike%
Kutter Crawford - 53% Strike%
Reid Detmers - 53% Strike%
Yoshinobu Yamamoto - 53% Strike%
No surprises on Sale, Greene, Ragans, or Glasnow of course, so we’ll breeze past them.
Validation on the hot starts from Crochet, Flaherty, Miller, Crawford, and Yamamoto. Crochet and Flaherty have been two of the most valuable late-round or free agent pickups at the position, and their 2024 breakout seasons are made more believable by their strong fastball performance. Would I still sell high on them? Yes, just a general rule is that it’s always good to be open to the idea of selling high on a surprise guy who starts the year extremely well - natural regression to the mean dictates that, but you shouldn’t be looking to just go out and take the best offer.
The two surprise names here are Hunter Brown and Reid Detmers, who have pretty bad ERAs right now (Brown = 7.79, Detmers = 4.96).
Brown has gotten strikes on the four-seamer, but he’s also given up four homers on the pitch. His main problem is that he’s been unable to get strikes on any other pitch.
The cutter, curveball, and splitter make up 42% of his pitch mix, and none of them have strike rates even close to the league average for those pitch types.
This does mean to me that all hope is not lost for Brown. He’s 25 years old in a good organization and has a lot of time left to make adjustments. If he can improve the curveball (which was his calling card coming up through the minors if I’m not mistaken), he could improve in a hurry and get back into fantasy-relevancy.
As for Detmers, it seems he just has a problem with consistency. He has had great weeks and months in the past, but has yet to put up a solid full-season. The four-seamer is working nicely this year with the 53% Strike% and really high 14.9% SwStr%, and the slider has an impressive 21% SwStr% and 48% Strike% as well. He’s given up seven homers, which is a lot, but the .297 xwOBA is really good and the barrel rate isn’t out of control at 9.8%. I think Detmers will be much better moving forward, and I would consider him one of the main buy-lows in deeper leagues right now.
Here’s everybody at 52% or 51% just to extend the list a bit without further commentary:
Carlos Rodon
Andrew Heaney
Ryan Pepiot
Shota Imanaga
Ryan Weathers
Reynaldo Lopez
Sinkers
This is a less common pitch, and there aren’t many guys really showing out with the sinker this year. Remember that the league average is 47%, so we’ll look at everybody above 49%, starting at the top (200 pitches minimum this time).
Ranger Suarez 54% Strike%
Javier Assad 53% Strike%
Chris Bassitt 53% Strike%
Brady Singer 52% Strike%
That’s the whole list for starters. Ranger Suarez has been just fantastic with the sinker, earning that elite strike rate while also getting the ball on the ground 69% of the time when it’s put in play.
Javier Assad was awful last year but has been better this year despite not getting many strikeouts, and no doubt that is largely attributable to this great sinker command he’s shown. The GB% is 53.5% and he’s thrown it for called strikes an absolute ton at a 26% Ball% (league average Ball% for a sinker is 33%). But I’m not buying Assad at all for fantasy, there just isn’t anything else here to hang your hat on and the history is really bad.
Chris Bassitt should start getting better results soon, he’s started slow for the last few years and that’s probably what’s happening now. He’s never been a strikeout guy, he’s relied on ground balls and command, and I think he’ll be fine this year - the sinker is still fine.
Brady Singer has had his moments, but overall I don’t think he’s a fantasy league guy save 14+ team leagues. He is 85% slider+sinker and he just cannot get a whiff on anything but the slider, and that tends not to work consistently.
The second clump:
Sean Manaea 51% Strike%
Jose Berrios 50% Strike%
Cristopher Sanchez 50% Strike%
Logan Webb 50% Strike%
Steven Matz 50% Strike%
Alex Wood 50% Strike%
The lesson of the sinker group is that you can go pretty far just by having a great four-seamer, but it doesn’t work the same way with the sinker. The sinker is a better complementary pitch rather than a foundational one. And that’s what we see with this group, besides Webb. None of these guys have fantastic secondaries, and it lead to really inconsistent and overall mediocre performances.
Cristopher Sanchez is the one name here to look a bit further into.
So the sinker has landed for called strikes a bunch, but the 5.2% SwStr% is really low, even for a sinker. The changeup has that elite SwStr%, but you’ll notice that it goes for a ball a ton - meaning that if the hitter identifies it early they just let it fall out of the strike zone for a ball. So it’s a good pitch but far from where you’d want it to be, and the sinker isn’t quite good enough to make up for it. Sanchez will have some good starts, but I think overall it’ll be pretty mediocre and he might end up back in a bullpen role eventually.
Cutter
This is even a shorter list, because not many pitchers feature cutters as a significant part of their arsenal. But a few names to hit on:
Clarke Schmidt - 51% Strike%
Corbin Burnes - 50% Strike%
Kutter Crawford - 49% Strike%
And that’s the whole list. Those are the only three starters who have thrown at least 200 cutters with a Strike% at or above 49%.
It is Crawford’s second appearance here, so he’s earning strikes with multiple fastballs which you really like to see. I think his early season success will continue.
Clarke Schmidt is having a bit of a breakout season. The cutter is solid (15% SwStr%, 51% Strike%, 33% Ball%, .315 xwOBA), but not a ton else:
I think he’ll probably fall onto some tougher times soon, especially when he has to face some of the league’s better lineups (he’s faced just two teams I would say have good lineups so far).
So that will do it for this piece. Thanks for checking it out, subscribe for daily e-mails and become a paid subscriber to get everything else I do here including projections, custom reports, dashboard, and much more. Check out the about page here for details.