The Change: Scouting With Pitch Type Whiff Rates


We know, not only because of Taylor Jungmann, but also from the Brewers’ starter, that not all pitches thrown seldomly with good results will remain as successful when thrown more often. Sometimes pitches are successful because they are rare and unexpected. Any batter can hit an eephus if you tell them it’s coming, but your average eephus gets 7% swinging strikes, mostly because they are surprising.

That said, we have some research on what makes curves and changeups good in terms of movement. So if we combine a pitch with elite results in a small sample with an appraisal of how good the movement and velocity on the pitch, we should be able to say with some confidence that the pitch is good.

In order to find our subjects, I merely set the filter low for pitch types (40 pitches) and looked for starters with elite results on changeups, curves, and sliders. It takes 150 plate appearances for strikeout rate to be stable, so this is probably a small sample even for pitch type ‘strikeout rate’, but we’re scouting here, trying to find the elite before they are actually elite.

Changeups (average = 13%)
John Lamb (72 thrown, 25% whiffs)
Henry Owens (68 thrown, 22% whiffs)
Aaron Brooks (107 thrown, 21% whiffs)
Daniel Norris (114 thrown, 21% whiffs)
Nicholas Tropeano (62 thrown, 21% whiffs)
Raisel Iglesias (146 thrown, 19% whiffs)
Carlos Rodon (172 thrown, 19% whiffs)

Yes, John Lamb is far removed from his prospect status. But if you look at the 91.5 mph average velocity and look past him, you’ll be doing yourself a disservice. He’s a lefty, so that’s actually a tick above average. He’s got good rise on the four-seamer, decent movement on the changeup, and a huge 15 mph velocity differential between his fastball and changeup. His curve super slow (lower than 70 mph), but it has decent movement, and he goes to it less than an 87 mph cutter. He’s been healthy for two years now, and in those two years, he’s struck out more than a batter per inning. It may not look like ace stuff, but Lamb should be useful in all leagues, particularly in good matchups. Right now, he has the third-best changeup thrown by a starter, which might surprise people.

Boston’s Henry Owens had more prospect pedigree, but you could argue that the movement on his pitches is less exciting. Sure his change is cool, and it has the requisite drop if not great fade, and it’s a 13 mph gap in his case. But Owens uses his sinker half the time and doesn’t have good rise on his ball, so his velocity is more average than Lamb’s. His curve is also slow (72 mph), but he doesn’t have a cutter to give him something between his fastballs around 90 mph and his junk in the 70s. Owens is a lot closer to Lamb than people might like to admit.

Righty Aaron Brooks has a straight fastball without much rise, so right now he looks like a one-pitch pitcher. Well, he’s thrown 70 sliders at 86 mph and gotten good results (16% whiffs), so maybe two. But he’ll need to find some rise, or cut his fastball, or go to the sinker more (despite the fact that he’s given up homers on 2.9% of his sinkers) — he’ll need to do something to find that third pitch, and hopefully that pitch will leave his hand at 89 mph or better.

Daniel Norris is another well-thought of prospect type, and he’s pitching in a better park in Detroit now. His problems will not be uncovered by pitch type analysis. His changeup, slider, and fastballs all rate average or better by whiffs, and they all have the movement to match. Even his curve (-1x,-9z) is a big, huge 12-to-6 curve that should get tons of grounders (and does, at 57%). No The problem is that nearly half of his non-fastballs are balls, and he can’t command his fastballs that well either. Still, average velocity on a rising fastball, with a great change, a fine slider, and a big hook? That’s why people like this guy.

Nicholas Tropeano gets none of the love that Norris gets, but he shows up as a league leader in both changeup whiffs and slider whiffs (20%). And that’s true even if you … split out his splitter. The fastball is perhaps below average — hence the homer problems in the minors — but his new home park should help with that. He’s absolutely a name to watch for September starts, especially with Jered Weaver’s velocity in the 70s, Matt Shoemaker up and down, and Hector Santiago among the league leaders in batted ball velocity change in the second half (in a bad way).

Raisel Iglesias is one of two or three names that is mixed league worthy (we’ll round those up at the end). Like Tropeano, Igelsias also shows up as a slider leader (22% whiffs), but unlike Tropeano, the Cuban Red has an above-average fastball (7.6% whiffs, 92 mph). He’s closer to 91 mph in the sixth inning, but he’s still above-average in most facets of the game. Don’t look at the projections for Iglesias, who’s entire statistical history is small sample. He has all the parts and is only a hung slider and a bad sixth inning fastball or two away from being even better. Remember, he used to be a reliever, and has never pitched this many innings. He’s a great keeper league pickup, or name stash for next year.

Everyoneba knows Carlos Rodon, but they know him for the sliders, which have managed a 20% whiff even as he’s thrown 604 of them. He’s only thrown 172 changeups, but they’ve had good results, and they actually have great movement — two inches more drop and fade than the average change, with average velocity differential. It’s fair to wonder if he can command it, but Lance McCullers can’t really command his change, and he’s had better results. Rodon’s pieces are in place, and while it’s tempting to think it’s all about command, he’s totally the kind of pitcher that could overwhelm with stuff, if only he can coax the batters to swing. His swing rate is still below average because everyone is waiting for walks. There’s still enough here that he’s worth targeting in dynasty leagues while his value is down.

Curves (average = 11%)
David Hale (155 thrown, 21% whiffs)
Aaron Nola (175 thrown, 17% whiffs)
Chris Bassitt (168 thrown, 14% whiffs)

For his career, David Hale still has great results on his curve and change (20%), but it seemed like it couldn’t continue in Colorado. Well, now the curve has actually improved in the altitude, which is weird. Maybe the key is that it’s actually a slider, that’s how Brooks has it labeled, and the movement makes sense. Hale still has below-average fastball velocity, and some command blips that leave the change and four-seam vulnerable for homers (he gives up homers three times as often on those pitches as his sinker and slider). Given that his sinker gets the same whiffs as his four-seam, maybe Hale should drop the four-seam. He’s obviously a long-shot, but there’s still something here.

For a guy that was supposed to be all command and not great stuff, Aaron Nola has a fairly nasty changeup (16% whiffs) / curve combination. Again, like many of the guys on this list, Nola’s fastball velocity is below average and that will hold him back from stardom. Most of his homers come on the four-seam, too. But the four-seam gets three times the whiffs of his sinker, so there’s no magic solution for him. It’ll be interesting to see if he gives up fewer homers as the hits start falling into play more. He looks like a redraft league spot starter, since a strong offense at home in Philly might be a tough look for him.

Chris Bassitt has added almost two ticks on the fastball, and now has above-average velocity. He’s added an inch of drop on the curve since the beginning of the year, and now the curve looks like a legit out pitch. Bassitt has a whiff of Matt Cain about him — this curve gets muted results for a best pitch, but the slider (11% whiffs), and four-seam (8% whiffs) are average to above-average — and might be able to confound projection systems for a while in his prime, by sequencing well, taking advantage of his home park, and being able to break out a 96 mph fastball for whiffs late in the game.

Sliders (average = 13%)
Joe Ross (356 thrown, 27% whiffs)
Andrew Heaney (190 thrown, 26% whiffs)
Jonathan Gray (51 thrown, 25% whiffs)

Joe Ross doesn’t fit the mold we’ve created here, since we’re looking for smaller samples, but he had to be included just because it’s so remarkable how like his brother he is. He’s even better by this measure, since Tyson only gets 22% whiffs on his slider. Joe’s changeup is just as bad as his brother’s though, and his fastball is a tick or so slower, so Tyson’s career is about the best you can expect for Joe.

Andrew Heaney’s slurve is fierce, and it might be enough for him to be good, since he can chop it up and change speeds with it a little. The rest of the package is the question, since he has average velocity, and a change that has inspired different reads every time out. In aggregate, his change drops three inches more than his sinker, and goes eight miles per hour slower, though, so it’s a good pitch. Cleaned up mechanics have augmented good natural command, too.

You probably couldn’t get a more different pitcher to end with then Jonathan Gray, who throws fire and doesn’t have great command. But Gray’s slider, at 87 mph, has the gas to be a strong second offering. We know his 94+ mph fastball is impressive, and it does get good whiffs (8%). So the question is his change, which has done okay so far (11% whiffs) and has an above-average velocity differential, but doesn’t drop much. He’s trusting it about as much as his slider, which is a good sign for now.


For dynasty leagues, Joe Ross is the prize good here. He may not pitch many more innings, but he’s shown the best results and has a great slider. Carlos Rodon has to be tied for first with him, for similar reasons, but his changeup should mean he has more upside than Ross. A tier below, I’d go Heaney, Iglesias, and Nola. The lefties get their own tier, with Norris heading it up, followed by Owens and Lamb. Gray is hard to place here, but the movement on his changeup is not impressive, and his park is not a plus. Tropeano, Hale, and Brooks are deep league fliers, still, but Tropeano is clearly the best.

Chris Bassitt is also hard to place, because losing any of that velocity means the whole thing plays more Kitchen Sink than Balanced Arsenal. He might be in the top five when it comes to spot starting down the stretch, though. It’s hard to point to one pitch as being his downfall, and his park will make for good matchups.

With a phone full of pictures of pitchers' fingers, strange beers, and his two toddler sons, Eno Sarris can be found at the ballpark or a brewery most days. Read him here, writing about the A's or Giants at The Athletic, or about beer at October. Follow him on Twitter @enosarris if you can handle the sandwiches and inanity.

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