THE BOOK--Playing The Percentages In Baseball

I want to especially point out this graph:
http://www.sonsofsamhorn.net/wiki/images/4/47/Guide2.gif

A spin x speed chart would also be cool.

I’m very excited about Daniel’s work and glad to see you giving him props here.  He deserves them.

I think he took the inspiration for that graph from my primer, or if he didn’t it’s very coincidental.  Which is fine with me if he did; I gave him permission to copy my stuff.
http://mvn.com/mlb-stats/files/2008/01/typical_spin_deflection2.jpg

I’m actually not completely happy with how I have splitter positioned on that chart.  It really should probably just be a bigger circle surrounding the changeup since splitters can have such varying movement.  A splitter with a low spin rate can end up where I drew it, but a splitter with a higher spin rate can end up on the opposite side of the change-up circle, or with a low spin rate and very inclined axis, it can end up sitting below the change-up circle.

Here’s a plot of typical pitch speed vs. spin deflection angle for a right-handed pitcher.

http://fastballs.files.wordpress.com/2008/04/typical_spin_deflection_angle.jpg

I actually got that chart from SoxScout, another poster on SoSH, who might have taken it from you, but I have no idea.

A spin / speed chart would be nice to add.

You should see someone like Buchholz’s changeup though, which actually lands in the cutter or slider version of the break chart.

Thanks for the shout!

I had seen the graph before and saved it, but it was only thumbnail sized.  When Pitch f/x exploded on SoSH I couldn’t remember where it was from and ended up just making a new one.  It’s definitely an invaluable reference.

Dan, very interesting.  I’m curious what Buchholz is doing with that pitch.  It certainly doesn’t move like a normal changeup.  I’ll have to look into that.

Are u using the MLB classification of pitches on gameday or are u using your own pitch classification?

MLB needs a bit more tweaking on their pitch classification IMO.

Fantastic chart in #3.  Good stuff…

I would be a little bit happier if these guys would take it a step further and communicate as if they were talking to the densest of the smart people (like me) that are likely to read these articles.

For example, what do ax and az represent in his spin formula, and in the speed versus spin chart, is the spin axis revolutions per second, or spin axis, or the pitcher’s SAT score, or the temperature created by the ball creating friction with the air…

MGL/#9, ax is the acceleration of the pitch in the x-direction (left-right), az is the acceleration of the pitch in the z-direction (up-down).

On Jnai’s speed vs. spin chart, spin is the direction of the spin axis in degrees.  The coordinate system is from the catcher’s perspective.

Cool stuff.  It would be a shame if the rumors are true and MLB takes this stuff away sometime later this year.

I don’t know who it is that is starting those rumors.  But, why would Sportvision convene a summit and invite fans and MLB.com people if they were going to shut this thing down?  Does it seem feasible that the 1 or 2 teams that are doing PITCHf/x right now will shut out the other 28 or 29 teams who are getting free work and exposure to free resumes on this, and letting the six or seven PITCHf/xers (Fast, Walsh, Kalk et al) who are doing this control the market?  Wouldn’t it make more sense for MLB to let this thing grow until they have some 50 or 100 people qualified and eager and battle-tested on this stuff, pick out 30 of them, and THEN shut it down? 

You’re going to need at least 16 teams forcing the issue onto MLB.com, as I see it.  Plus, MLB.com has its own agenda, and won’t necessarily listen to those 16 teams.  At some point in the next few years, MLB.com will be worth more than the other 30 teams combined.

Also, Inside Edge has been doing something like this for ESPN and some teams for a few years now (pitch types and pitch location).  This creates a better marketplace to compete against them.

If the rumor-starter wants to send me details in an email at tom~tangotiger~net (replacing the ~ with the appropriate character), I can keep things as confidential as required.  I’d like to know the basis here.

I don’t know if this is the source of Rally’s rumor, but it’s where I heard similar comments:
http://www.baseballthinkfactory.org/files/newsstand/discussion/mets_geek_peterson_interview_tom_tango/

Comment #1:

Not sure how this will affect the PITCH f/x sleuths out there, but I have it from a very credible source that MLB Gameday will remove the PFX data point from all pitches later on this year, most likely in the second half of the season. They’ll still post the type of pitch, speed at release, break, and result, but will no longer share the pfx data. [Edit: the reason, of course, is that some powerful people within baseball complained about the release of the pfx data, the same way the umpires union complained about the imposed strike zone on mlb gameday and had it removed… but this time, it wasn’t the umps complaining]

My take on the comment was that MLB.com was going to remove the PFX column from their Gameday display once they get more confident in their pitch identification accuracy later in the year.  It would still be available in the underlying data, however.  That’s the best explanation for the first part of the comment, but it doesn’t explain the second part of the comment.

The explanation that MLB is going to take away all the PITCHf/x data fits the second part of the comment but doesn’t really make sense with the first part.

Mike, thanks. That was not obvious, so I don’t feel like such an idiot for not knowing it.

A couple of PITCHf/x glossaries I have bookmarked:

Mike Fast’s:
http://fastballs.wordpress.com/2007/08/02/glossary-of-the-gameday-pitch-fields/

Professor Nathan’s:
http://webusers.npl.uiuc.edu/~a-nathan/pob/tracking.htm

Is there a way to contact Jnai (Dan Brooks)?  I put a comment on the pitch F/X wiki but there has been no reply.  I just want to ask if he would share the code to the tool he created.  I have no experience creating a web based graph but do have pitch f/x data I would like to graph.  The code he used in the tool seems to be using a PHP graphing library to generate graphs on the fly.  It would be interesting to see how that works.  Thanks.

I passed along the message for you…

jnai, aka ieshan, aka Dan Brooks, has a real name to his website:

http://www.brooksbaseball.net/