Cool stuff, thanks for the research. I'd be curious though what your thoughts are on Mussina. If his release point is different for each type of pitch he throws, couldn't hitters pick up on that and know what type of pitch is going to be thrown? Obviously he's been pretty successful thus far in his career so history suggests that batsman aren't doing this. BTW, I suggest you use Young Joe Sheehan or some moniker like that to avoid confusion for the rest of us in the SABR community.

Now here's two things I love, slapped together: XML and Baseball stats. YES!! YEESSSS!!

I don't know what's going on with Mussina's release points. I agree that the different release points would appear to tip his pitches and I originally thought the differences were related to his tiring as the game went on or that he was struggling with his mechanics and couldn't throw strikes from one place. When I tested these ideas though, neither looked as plausible as the pitch type idea. He could also be physically moving side-to-side on the mound before he throws, which would change his release point, although I think that would tip hitters too. Another possibility is that in his one playoff start he happened to have two release points.

Very cool stuff. Are there any sites that explain how to access and use the XML files?

P.S. Maybe you should go by Joseph Sheehan.

I remember back when you could use Gameday for mundane matters like finding out what transpired in a game. MLB.com has a bloated application that eats up RAM and processing power.

I just need the facts when I'm following online. Remember that Gameday is the application of choice if you are at work and you just want to dip in from time to time to see what's happening. When I'm at work, I really don't care what the break on Kenny Rogers curve is. If I really cared, I would watch the game.

I don't want a scattergram. I just want to know who's ahead. You know. Stuff like that.

Bob, your concern is best addressed on the MLB.com blog. There's nothing stopping MLB.com from providing the Classic Gameday, and the enhanced one.

What Joe has done here is beyond fabulous, and at the same time, barely scratches the surface. Huge applause.

I don't mean to denigrate Mr. Sheehan's work here, but he was giving a positive review of a consumer product that I didn't think worked well at all. It may have worked well for what Mr. Sheehan wanted, but my expectations are different than his. Obviously many of the readers of this site seem to enjoy the Gameday features, I just don't happen to be one of them.

Joe, how do you convert the coordinate system provided on the XML file to feet?

Max, I believe that the data given in the XML is in feet. The fields that represent the release point are x0, y0, and z0. y0 is 55 for every pitch, and x0 and z0 are the x,y values that I graphed. 55 feet away from home plate is a good place to begin tracking the pitch, you would usually pick it up after a pitcher drives off the rubber. z0 is the height of the ball at the release point, and the numbers given for z0 (roughly between 6-7) are the right size it were measured in feet. x0 is the horizontal distance away from a stating point that the ball is at release. The values for x0 also make sense if it were measured in feet.

There really isn’t any documentation about whats in the fields, so I made educated guesses about what different fields mean. In the words of Charles Barkley, I could be wrong about them, but I doubt it. Although if anyone has ideas about what a field means or other things you’d like to see done with the data, I’d love to hear from them.

MLB.com set up the application now so you can turn off the more sophisticated pitch data when viewing the game in real time. But you can go back and get it later.

This would seem to be a good compromise.

Joe, I want to thank you for showing us just some of the uses of this data. I have been looking at the xml data in the past few days trying to break down what all the data means.

Your explanation of the x0,y0 and z0 values being in feet has helped quite a bit.

For anyone else who wants to break some of this data down here are some other things that I think I have figured out.

the vx0, vy0 and vz0 are the speed in feet per second in each direction. I confirmed this by checking the speed of various pitches in mph at their start speed and comparing that to the value of vy0 and they always matched up (.6818 mph = 1 fps)

the values for x and y for the pitch location are in centimeters. I believe this to be the case since when you look at pitches on the right edge of the strike zone and the left end of the strike zone they are roughly 40 apart. 42.5 centimeters is equal to 17 inches which is the width of home plate.

sz_top and sz_bottom are the height of the strike zone for the current batter again in feet.

I am still looking into what pfx,pfy, px and py are. hoping I can crack that this weekend.

Just thought that I would share what I have learned. Again I might be completely off on these but they all seem to make sense and work with the pitches I have watched.

I'm thinking the following: px and pz is the location of the pitch in the strike zone in feet (with p standing for pitch). x and y would be the location in the strike zone as well, but uses the old classic gameday coordinate system. How those values are arrived at, whether used to convert to feet to find px and pz or is totally determined seperately by some person watching the inputting the locations of the ball when it crosses the plate, I don't know. I don't think this coordinate system is actually centimeters, though that was a good guess. I made a couple equations in excel using Harden's Wednesday pitching data. With y being px in feet and x being "x", I got the equation: y = -0.03x + 2.9657 and those number values would be in feet. There's .0328 feet in one cm, so you were close with that assumption, derek. Then with y being pz and x being the y coordinate you get the equation y = -0.0428x + 8.7438. Not there was imprecision and that equations just document the general motion; meaning there's is not an exact correlation between px and x, and pz and y. The rho-squared value for the first was 0.9393 and seoond was 0.9171. If there was an exact correlation those values would have 1.00. So what accounts for this error? Do the values change with changes in the strike zone or are these values totally found seperately with the px and pz found by the camera and the x and y determined by someone watching the game and so the rho-squared value is actually measuring the human error.

I didn't know what the vx0, vy0 and vz0 values meant, but what you said makes sense. And if not for Joe's article I would have never ran across this stuff and had little idea what it meant.

I've been looking for this data online for a few days and haven't been able to find it. Perhaps someone here will be find enough to direct to a link where I can download it.

To clarify, yes, I found the link in Joe's article. That helps. But is there an html version of a page that makes navigation easier? Also, is there a complete set that could be easily downloaded?

I'm pretty sure that the regular x and regular y are the pitch coordinates when not using enhanced gameday. These are available for pretty much all of last season, even prior to enhanced. I don't know that they translate to centimeters at all or if they are just plotting coordinates. If you look in the hit location xml file, there are xy coordinates there as well that are also scaled at 0:250.