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Stephen Sutton-Brown

@srbrown70.bsky.social

2.8K followers 120 following 1.7K posts

Braves, heat maps, cars, tractors, and music Creator of StuffPro and Arsenal Metrics at Baseball Prospectus He / him

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Stephen Sutton-Brown @srbrown70.bsky.social · Jan 17

I have never been more excited to release an article: Introducing BPro’s new Arsenal Metrics! www.baseballprospectus.com/news/article...

Introducing BP's new Arsenal Metrics | Baseball Prospectus

A new way at quantifying not just individual pitches, but how they work together.

www.baseballprospectus.com

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Stephen Sutton-Brown @srbrown70.bsky.social · 7h

ok it is def having an impact on the model. Here's average distribution of Pitch Type Probabilities when a pitcher throws their FS if we calculate PtP only using each offering's release point distributions. Next is for Bryce specifically when he throws his FS. FS is much more obvious for him.

Stephen Sutton-Brown @srbrown70.bsky.social · 11h

later tonight i can see how his pitch type probability distributions compare to league if I look just at the release portion. basic idea is what's the probability this pitch is any one of his offerings given the release point from batter's POV plus some additional uncertainty

Stephen Sutton-Brown @srbrown70.bsky.social · 11h

that would stick out, as the model calculates pitch type probability based on release, on release and initial trajectory, then finally (what's used in production) release, initial traj. and usage rate. it does look a little less apparent from batter POV though

Stephen Sutton-Brown @srbrown70.bsky.social · 12h

it's like when kids grow faster than their coordination can keep up

Stephen Sutton-Brown @srbrown70.bsky.social · 12h

i'm sure someone has written about this but strange to me how much bryce uses his four-seam given how broad his arsenal is

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Stephen Sutton-Brown @srbrown70.bsky.social · 13h

it is, i can't get over how insane it is

Stephen Sutton-Brown @srbrown70.bsky.social · 13h

If you sort instead by lowest expected run value if swung on it looks less impressive since it had a lower probability of a whiff than these others. That Devers homer off Strider was insane

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Stephen Sutton-Brown @srbrown70.bsky.social · 13h

On Judge's HR against Varland, PitchPro estimated an expected wOBACON of just 0.139 if put in play. That's the second lowest E[wOBACON] for any home run in 2025.

Note that Bleday's homer off Matsui came off the bat at just 94.8 mph and snuck over the wall.

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Stephen Sutton-Brown @srbrown70.bsky.social · 15h

incredibly useful

Mike Petriello @mikepetriello.bsky.social · 1d

Another new thing: we add so much cool stuff to Baseball Savant that it's not always easy to keep track of, so here's a good 'whats new' page we'll do our best to keep updated

--> baseballsavant.mlb.com/changelog

Savant Changelog

Baseball Savant

baseballsavant.mlb.com

Stephen Sutton-Brown @srbrown70.bsky.social · 19h

*logging on to read some very serious baseball writing*

Stephen Sutton-Brown @srbrown70.bsky.social · 1d

are you able to say which baseball projects you've used BART for?

Stephen Sutton-Brown @srbrown70.bsky.social · 1d

Repurposing the SaberSem pitch detection algo to see what pitch types and movements a batter might expect when they see Trey Yesavage's SL out of hand (h/t @enosarris.bsky.social on Rates and Barrels)

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Stephen Sutton-Brown @srbrown70.bsky.social · 2d

how i'm spending my time between innings

Stephen Sutton-Brown @srbrown70.bsky.social · 2d

Pulling the Arsenal Metrics for it, lots of deception

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Reposted by Stephen Sutton-Brown

Chris Hanel @chrishanel.com · 10d

a remix of a yoda meme:

after Sending out Treinen 37 times in a row while standing in front of the bullpen at 1:34 am

[picture of Dave Roberts looking dazed and confused]

2:12am... going back for more Treinen

[picture of Dave Roberts walking with a weird facial expression]

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Stephen Sutton-Brown @srbrown70.bsky.social · 2d

He saw my tweets about Skubal
bsky.app/profile/mich...

Stephen Sutton-Brown @srbrown70.bsky.social · 2d

I'm generally of the belief that over a season challenging guys in zone is worth the extra hard contact (once again looking at you, Blake Snell): You to prevent walks and falling behind in the count, and you avoid running your pitch count up. But in a single series I'm not sure.

Stephen Sutton-Brown @srbrown70.bsky.social · 2d

Will try to do a few of these post-mortems this October. I think it helps getting a better sense of what the model sees and how well that matches my own intuition.

Stephen Sutton-Brown @srbrown70.bsky.social · 2d

Something to remember about pitch models is they (correctly) don't think a HR is the most likely outcome of a meat ball.

Here are the two HR Skubal gave up thru the eyes of PitchPro. Model expects <50% chance of in play, & sees a 1B or 2B as far more likely than a HR if in play.

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Stephen Sutton-Brown @srbrown70.bsky.social · 3d

we call it a sweeper

Stephen Sutton-Brown @srbrown70.bsky.social · 3d

it's time to spidey save the day!

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Reposted by Stephen Sutton-Brown

KD Casey — Read Breakout Year Today! @kdcaseywrites.bsky.social · 4d

thinking about this for no reason

1st Viscount Craigavon @cdgoldstein.baseballprospectus.com · Jul 31

if you hadn't seen

Atlanta Braves trade RHP Rafael Montero to the Detroit Tigers for INF Jim Jarvis.

A few weeks ago I was walking around the neighborhood with my kids when they stumbled across a cardboard box marked “free” and a knockoff-Lego remote control car set inside, still sealed. I couldn’t say no to my son—the box literally said free on it, what were my grounds—but that set was not free. It was free monetarily, but it was not free in the sense that it was a pain to build, the instructions were terrible, and you just knew those pieces were going to get mixed in with all the real Legos. As a kid, you don’t understand yet that money is often not the main price of things: there’s also time, and energy, and love. All of these things can be charged to you.

Depending on how the cash gets considered, the Tigers may have gotten themselves a free middle reliever—Jim Jarvis sounds like one of those 1970s shortstops that held the bat eight inches above the knob, and also hits like one—but Montero will not be free. The cost will reveal itself in time.

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Stephen Sutton-Brown @srbrown70.bsky.social · 4d

i need closer games to justify my not doing yard work

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Stephen Sutton-Brown @srbrown70.bsky.social · 4d

something i've thought about a lot since doing more research is whether the Arsenal Metrics are assuming too little visual uncertainty at release point. Freddy Peralta is a good example of that. He's got distinct arm angles for FA/CU and CH/SW, yet it doesn't appear to be hurting his results.

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Reposted by Stephen Sutton-Brown

JJ Cooper @jjcoop36.bsky.social · 5d

Adjusted pitch plot to reflect where the strike zone at the midpoint of the plate.

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