The updated version of this catalog is now hosted by The Hardball Times.

In the 2006 postseason, Major League Baseball introduced a feature they called Enhanced Gameday, based on the PITCHf/x camera system from Sportvision. Based in Mountain View, California, Sportvision is also the creator of the yellow first-down line that appears on football telecasts. The PITCHf/x cameras capture the speed and location of the pitched baseball throughout its flight to home plate. Dr. Alan Nathan has a good description of how the system works on his Physics of Baseball site. MLB has, for now, made this data accessible in the XML files freely available for download from its Gameday website.

This summer, a number of baseball analysts have begun using this new data to tackle questions heretofore out of the realm of the common researcher. Others have made brief summaries of the published research, but I haven’t seen a comprehensive catalog. What follows is an attempt at such a catalog. If I have overlooked anyone or left out any articles, please bring it to my attention. Order is not necessarily a reflection of importance, but I have tried to list the earliest and/or most groundbreaking work first.

(If you want a quick introduction to the field without having to read through all the articles below, I recommend John Walsh’s “In Search of the Sinker” and Joe P. Sheehan’s “More Fun with Enhanced Gameday”.)

First and foremost among these analysts is Joe P. Sheehan, who has published nine articles on the topic at Baseball Analysts, one at The Hardball Times, and one at his Juice of Jesus blog.

  • On February 28, he published “Fingerprinting Jeff Weaver”, an article about pitcher Jeff Weaver, classifying his pitches based on his performance in the 2006 playoffs with St. Louis.
  • On March 29, he published “Enhanced Gameday”, an article about various pitchers from the 2006 playoffs, looking at pitch location, release points, and classifying pitches for Mike Mussina.
  • On April 18, THT published “Another Look at Enhanced Gameday”, an article about pitch selection, velocity, and classifying pitches for Felix Hernandez and Kevin Millwood.
  • On April 19, he published “More Fun with Enhanced Gameday”, an article about consistency of pitch movement, location, and release points, and classifying pitches for John Lackey.
  • On April 26, he published “That Sinking Feeling”, an article about the two-seam fastball, examining pitchers Derek Lowe, Aaron Cook, Brandon Webb, and Carlos Silva.
  • On May 11, he published “Location, Location, Location”, tracking the location, BABIP, and swing percentage of pitches in different grid locations around the strike zone.
  • On May 25, he published “Dangerous Curves”, on the break of the curveball and pitchers Barry Zito and Rich Hill.
  • On June 14, he published “Ch-ch-ch-ch-changes…”, on the effectiveness of the changeup and pitchers Cole Hamels, Josh Beckett, Trevor Hoffman, and Johan Santana.
  • On June 28, he published “Is There Something in the Way It Moves?”, on pitcher Roy Halladay and the consistency of his stuff from start to start.
  • On July 13, he published “Under Pressure”, on pitchers Jake Peavy and Dan Haren and their pitch selection in high-pressure versus low-pressure situations.
  • On July 26, he published a collection of PITCHf/x-related notes under the title “Not an Article about Pitching at Altitude”. He discusses preliminary data about the effect of altitude on the break of pitches, and updates his BABIP charts from “Location, Location, Location”.

Another major researcher in the field is Dan Fox, author of the Schrodinger’s Bat column at Baseball Prospectus and the Dan Agonistes blog. Most of his work is available for BP subscribers only. His June-July series on Hernandez, Wakefield, and Matsuzaka is a great primer on classifying pitches.

A third important contributor is John Walsh, a nuclear physics professor at the Istituto Nazionale di Fisica Nucleare in Pisa, Italy. He has published several articles at The Hardball Times:

  • On June 6, THT published “In Search of the Sinker”, one of the definitive articles on classifying pitches. In this process John examines the sinking fastball and pitcher Randy Wolf.
  • On June 26, THT published “Schilling’s Aching Schoulder”, an article about detecting Curt Schilling’s shoulder injury in the Enhanced Gameday data.
  • On July 11, THT published “Strike Zone: Fact vs. Fiction”, an article about the strike zone, as called by the umpires, versus right-handed and left-handed batters.
  • On July 25, THT published John’s followup article “The Eye of the Umpire”, containing some refinements to the previous article. The pair of articles are an excellent beginning to strike zone analysis.

Next we come to John Beamer, author of a couple articles at The Hardball Times:

Over at the Go Rangers! blog, Steve West is another PITCHf/x researcher.

  • On June 14, he published “Rotation Release Points”, an article about the release point consistency of the starting rotations of Texas, Anaheim, and Oakland.
  • On June 18, he published “Rangers Rotation Pitch Types”, an article classifying the pitch types of Texas pitchers Kevin Millwood, Brandon McCarthy, Kameron Loe, Vicente Padilla, and Robinson Tejeda.
  • On June 25, he published “Rangers Rotation Release Points Redux”, an article examining whether the Texas starters were tipping their pitches by varying release points.
  • On July 12, he published “Pitch Break Angle vs Length”, and article about classifying pitch types using these two new PITCHf/x parameters. This article is a useful complement to the pitch classification work of Fox, Walsh, and Beamer.
  • On July 30, he published “Do Pitchers Affect the Strike Zone”, a look at batted ball results plotted against pitch location in the strike zone.

Next up is Bill Ferris at the Detroit Tigers Weblog with a few articles on Tiger pitchers. Because Bill is so prolific a blogger, I may have missed something of his on the topic.

Louis Chao has one article on The Hardball Times. Hat tip to Whither for pointing me to his first Chinese-language article at Andre’s Baseball Blog.

  • On June 26, he published, in Chinese, “Diggin’ in on the Sinker”, an article looking at sinkerball pitchers. Putting this article through Google Translate to English makes it clear why that tool is still in beta. ;)
  • On July 12, THT published “Another Look at the Sinker”, an article comparing the two-seam and four-seam fastballs and looking at pitcher A.J. Burnett.

At the beansTown blog, Steve Calcagno has one article.

Over at the U.S.S. Mariner, Dave Cameron has one article using Enhanced Gameday.

A Devil Rays’ fan who posts around the web as ultxmxpx has a website where he posted some Enhanced Gameday pitch analysis.

  • On June 3, he posted “Shields/Kazmir pitch selection” as a topic on the RaysBaseball forum.
  • On July 10, he published this list of pitchers and contact rate on their various pitches, which he had classified.

Anthony has Enhanced Gameday stuff scattered here and there throughout his blog at Friar Watch.

There are also some other Chinese language articles on this topic. I wish I could understand a bit more than what I can gather from Google translations, but I’ll present them here for those of you who do know Chinese.

Even if you’re an English speaker, you might be able to gather something from the Google translation and the graphs at Cafe Whither. Thanks to Whither for the first link.

And here are a couple other Chinese language articles.

I hope to contribute a little of my own work in the near future, but I felt the right place to start this discussion was with a recap of what has been done. Enjoy!

Update: New articles listed in this post.

Full list of articles by author.

Full list of articles by date.

Articles about pitchers listed by pitcher.