Robert Stock

I’m a baseball player. I’ve never written a single line of code in my life. But over the last few months, I used AI to build a pitching analytics platform from scratch. 8.9M pitches. Custom ML models. Total transparency. Here is a look at what happens when you give an interested athlete access to AI:

@BachTalk1 @JonPgh @pitchprofiler Opening day I’ll have my revised models up I promise

@RobertStock6 @JonPgh @pitchprofiler Give us your analysis @RobertStock6

Roki Sasaki's fastball is a problem last year: 312 pitches, 96.1mph, 5.8% SwStr%, 46% Strike%, 6 HR spring: 65 pitches, 97.6mph, 4.6% SwStr%, 32.2% Strike%, 2 HR League averages for a four-seamer for context: 10.6% SwStr%, 50% Strike% @pitchprofiler gives it a 92 Stuff+

Has this always been allowed?!?!?

@drivelinekyle This is the coolest thing I’ve ever seen

Aura farming. Personally a big fan of the sunglasses on the mound. Wasn't even aware they were allowed anymore.

@JonPgh @pitchprofiler That’s what all those trackman and edgertronic cameras are for in the bullpens. It’s VERY hard to change the shape when you throw it as hard as you can. Relatively easy submaximal velocity. Also some easy gains from different grips.

@RobertStock6 @pitchprofiler Is it hard to change the shape?

@JonPgh @pitchprofiler If Tyler Rogers threw Sasaki’s fastball he’d be the GOAT

@RobertStock6 @pitchprofiler I have learned recently that it doesn’t move in a way that properly avoids the regular bat path or something I’m getting there

@NoogaBaseball Throwing from the highest slot in baseball will put more strain on the shoulder, for sure. Tradeoff between being more effective and staying healthy.

Hmmm, maybe throwing from an extremely over-the-top arm angle isn't a great idea? I actually just looked up Trey on @RobertStock6's site yesterday (linked here) and saw this 99th-percentile value (guessing it might be a true 100th-percentile situation even) app.stockyardbaseball.com

@Alex3tats @KasperStats 😂😂😂

@KasperStats @RobertStock6 He served in Mexico aswell

Today I found out Robert Stock missed 3 seasons of MLB baseball to fight in the Korean war from 2022-2024. Thank you for your service Robert 🙏

I’m not sure we’re talking about the same thing. I’m saying that the things that elite pitchers do that are “different” from one another are unlikely to be important to mechanics. Such as if you bring your arms over your head in your windup. Or point your toe up or down as you lift your leg, etc.

@RobertStock6 @GoJags5528 Couldn't one argue they're harmful in the long run though? (Because they'll lose velo) Though in pitching it can be helpful in the short run (having unique mechanics is more deceptive)

If you wanna analyze good pitching mechanics, you should basically never look at someone in their 20s. A young pitcher can get away with so many things that will eventually derail them because they have a fresh set of tendons, ligaments, and nerves to degenerate. Look at the guys who do it all for a decade. They’ve proven they have all the components you should be interested in.

@OnePitchOneSoul @GoJags5528 "Half the distinguishing qualities of the eminent are but exaggerated defects." - had to look it up haha. That certainly applies here, but I’d say “unimportant” rather than actually harmful.

@RobertStock6 @GoJags5528 "Half the distinguishing qualities of the eminent are actually disadvantages."

@GoJags5528 @OnePitchOneSoul All of them! You want to try and look at the best of the best and find the similarities, and that tells you what you should be trying to do too. Whereas if one guy does something unique, that’s not (probably) not an integral part of good mechanics.

@RobertStock6 @OnePitchOneSoul Who are some of the longer tenured pitchers that you enjoy watching and studying?

@OnePitchOneSoul Basically yes. They won’t be able to sustain their high velocity for as long as a pitcher with “elite” mechanics would. Looking at only guys with a long enough tenure helps weed the other guys out.

@RobertStock6 Interesting perspective, so you've seen pitchers who compensate through bad positions tend to lose velocity faster?

@PeterAppel23 The very best ones blend stats like what SIERA use with stuff models. And none of them are public. But that's being pedantic I know, haha 🤣

I asked Claude to rank the best ERA estimators to predict future performance for pitchers. 1. SIERA 2. xFIP 3. xERA 4. FIP 5. K-BB 6. ERA I tend to agree. What do you think?

@RBunikiewicz And good mechanics are the common things that 95% of the best pitchers do. They’ll have little quirks, but elite mechanics look extremely similar when you put them side by side.

@RBunikiewicz The best pitchers have the following - Elite pitches - Good command - Durability Basically impossible to know durability until they’re in their 30s. They could be wearing down fresh body parts and would outwardly appear the same as someone who is not.

@PatSullivan05 Can you run it for like 10 years instead of 1? Curious how that would look.

@RobertStock6 Intuitively, guys who create contact stay fairly in carrying that on; more volatility in moving runners.

Runner advancement isn’t simply a function of putting the ball in play. Some hitters consistently outperform the baseline and Isiah Kiner-Falefa stands out as a dink and dunk hitter creating impact beyond face-value stats.

When Claude usage runs out for the next 24 hours and I look at Codex like

@ElongMa159311 @SoccerPatrik @vasuman So Metaverse is the VR stuff they were trying to get every day adults interested in? Like at the office and stuff?

@RobertStock6 @SoccerPatrik @vasuman No it’s not the other guy is just pulling shit out of his ass

As someone who worked at Reality Labs: the Metaverse had real legs but was obliterated by middle management completely out of touch with how young people actually use technology. I built a V1 tool that game developers genuinely needed, and the moment it was done, it got shipped to a team in London (to die), and I was reassigned to a "higher-priority project" that zero developers asked for. Multiply that by every team, and you'll understand why this never took off yet cost 80 billion.