The Good Stuff: Finding the Best Pitches in Baseball

Who throws the best fastball in baseball? Noah Syndergaard throws his fastball 98 mph on average, tops among all starting pitchers. Justin Verlander’s has the highest spin rate—over 2600 RPM—and over 11 inches of vertical movement. Or do we approach the question from a results standpoint? Jacob deGrom’s fastball has the highest whiff rate for a starter. Of course, there’s no right answer to that question, but it helps us start thinking about what characteristics make for a good pitch.

Yesterday, I introduced a new way to evaluate a pitcher’s raw stuff, an evolution of the pitch arsenal scores I’ve been using in my series previews for a few years now. Given the raw characteristics of a pitch—its velocity, movement, and command—we can calculate an arsenal score to compare against the pitch’s peers. I call this new metric Stuff+ and I’ll be using it in my series previews and elsewhere on the site this year. To get all the details and an inside look at how the metric is calculated, you really should read part one before reading on.

Now that we’ve established the methodology, let’s dive into specific pitch types and try and answer the question I posed above. Along the way, I’ll point out some shortcomings I’ve noticed with Stuff+. The tables below will show the combined Stuff+ score for that particular pitch type and the percentile ranks for each component to give you an idea of what makes the pitch stand out.

I guess we have the answer to our opening question: Jacob deGrom throws the best fastball in baseball. Three members of the Astros rotation appear on the list above, which seems like bad news for the Mariners. Houston’s pitching staff has received a lot of attention for throwing more and more breaking balls, but they still value an excellent heater. Both Verlander and Gerrit Cole possess great secondary pitches but their repertoires find their foundation in their fastballs.

In the comments on the piece yesterday, there was a bit of discussion about what a metric like Stuff+ can’t account for. Pitch sequencing is a big piece that remains a mystery. Another piece that’s missing—and I think its revealed in these four-seam fastball scores—is how a pitcher’s mechanics, arm slot, and deception play into the effectiveness of a pitch. Max Scherzer might be the prime example of this. He throws from a lower arm slot than normal and his fastball doesn’t get as much “rise” on it when compared to the average four-seamer. Along with his spotty control of the pitch leads to a Stuff+ score of 110, still above average but nowhere near the best in the league.

One of the main reasons why Garrett Richards has the highest overall Stuff+ score for his repertoire is because his sinker is just so good. Not only does he throw it extremely hard, he also gets the most horizontal movement on it because the spin rate is so high. We also see Chris Sale show up with his excellent sinker. He may not throw it with impressive velocity but his ridiculous arm angle gives the pitch unreal movement both horizontally and vertically.

Walker Buehler’s cutter is outstanding in three of the five components but its Stuff+ score is really hurt because he can’t locate it very well. Introducing a cutter into his repertoire helped Nathan Eovaldi take a big step forward last year. It’s good to see that not only did it help out the other pitches in his arsenal but it’s an outstanding pitch in its own right.

Changeups are a really interesting pitch type, especially when you look at them through this lens. I’m assuming the fastball-changeup velocity differential is more important that straight velocity, but there’s a group of pitchers who throw very effective hard changeups (Syndergaard, Stephen Strasburg, Carlos Carrasco) who grade out poorly in Stuff+. The research says a larger velocity gap between a pitcher’s fastball and his changeup is better for generating swinging strikes, though there is some evidence that a hard changeup is effective in keeping the ball on the ground when a batter makes contact.

Of the pitchers listed above, I’m most surprised by Luis Castillo. He’s known for his excellent fastball velocity and killer slider but it’s his changeup that grades out as his best pitch via Stuff+. Then there’s the group of pitchers with poor fastballs but make up for them with excellent changeups. Ty Blach, Zach Davies, and Chase Anderson are all changeup specialists which helps their mediocre fastballs play up.

Sonny Gray’s curveball is his signature pitch and now we have data to show just how good it really is. It receives outstanding grades in four of the five categories. Cole was specifically targeted by the Astros because of his excellent curveball just like Charlie Morton (135 Curveball Stuff+) and Collin McHugh (121 Stuff+).

One of the shortcomings of the control component I’m using is it negatively impacts pitchers who throw their breaking balls off the edge of the zone to get swinging strikes. James Paxton is a prime example. He generates an excellent whiff rate on his curveball but it has a merely average Stuff+ score because he doesn’t “command” it well. Is that because he’s locating the pitch outside of the zone on purpose which negatively affects his Edge%? This is where a pitcher’s intent with a pitch is lost on our control component.

Yovani Gallardo?! That’s a surprising name. That group of five pitchers with really poor vertical movement on their sliders is really quite interesting. They make up for the lack of depth on the pitch with excellent velocity, and either good command or good horizontal movement. It’s nice to see Luis Severino on top of this list since he makes his living off his slider, though the problems that dogged him towards the end of last year are revealed in his control score.

The same problem we saw with curveballs stays true for sliders. Some consider Chris Sale’s slider to be the best in the game, but it grades out as a below average slider via Stuff+. Some of that is because its one of the slowest sliders in baseball, but he also doesn’t “command” it well. Is that because he purposefully throws it out of the zone to get a swinging strike? There’s only so much we can capture in a command metric without accounting for the pitcher’s intent.

The Mariners Starting Rotation

Now that we’ve looked at the best pitches in the game, let’s turn our attention to the Mariners pitching staff.

Marco Gonzales makes up for rather mediocre velocity and movement with excellent control of all his pitches. His curveball really improved last season and that pitch was a big reason why he was so successful so its nice to see it grade out so well here.

Like Gonzales, Leake gets by with poor velocity by commanding his non-breaking pitches very well. His two breaking balls have excellent movement profiles but may suffer from the shortcomings I discussed above. His slider is actually a pretty effective pitch if we’re evaluating on outcomes.

Wade LeBlanc has one of the slowest repertoires among all starting pitchers and that really drags his Stuff+ scores down. And yet, he’s able to generate whiff rates around or better than average on all his pitches. He’s the type of pitcher that Stuff+ just doesn’t know how to handle. On paper, LeBlanc shouldn’t be nearly as good as he was last year, and yet that veteran guile and pitching knowledge helped him overcome the deficiencies of his raw stuff.

:crying: It would be an interesting exercise to try and see how peak-Félix would grade out via Stuff+ (unfortunately the data just doesn’t go back far enough to do this). Unsurprisingly, modern-Félix’s stuff has deteriorated to an extreme degree. Maybe the most surprising grade is his signature changeup. It’s never had a good velocity differential, but that gap is even smaller with his fastball’s velocity plummeting. He gets excellent movement on the pitch but simply can’t control it. His command of his entire repertoire seems to be the biggest hurdle he faces in trying to reinvent himself with diminished stuff. He can’t get by on pure stuff anymore and his command just isn’t good enough to sustain any kind of success.

If you’re interested in playing around with the entire dataset, I’ve made it available here (please make a copy for your own use if you plan on spending significant time with it). There’s sheet labeled “Query” where you can select the pitcher and the data will automatically populate. The “Calculator” tab is a blank slate where you can input your own components (or pull them from Brooks Baseball and Baseball Savant if you want) and it will spit out Stuff+ scores.