02 July 2007

Today I've got a piece over at the Hardball Times about Tim Hudson that uses detailed pitch-by-pitch data from mlb.com. The data tracks the trajectory of the ball from the hand to the plate and allows you to measure start and end velocity, pitch location, release point and pitch break. Those of you who regularly use Gameday may recognize that is where the data comes from. Using these data opens up a whole new world of baseball analysis. Here are some cool things we can do with the data:

• Work out how many pitches a hurler throws and in what situations a hurler uses a particular pitch
• Look at signs of injury (slowing velocity) and tiring
• Identify pitcher/hitter hot and cold zones
• Look at where in the strike zone a hurler likes to throw

Anyway, if you click on the link you can read a full analysis of Tim Hudson using these data. As a teaser here is one graphic showing break (in inches) and speed. Vertical break is on the y-axis and horizontal break is on the x-axis. Any difference from zero is the break relative to a pitch with no spin. For instance, a +10 on the vertical break axis indicates that the pitch rose 10" relative to a pitch with no spin -- a fastball typically does this as the backspin provide a bit of lift. (Note that over its entire trajectory the pitch falls relative to the point it was thrown.) Earlier in the week I had a short email discussion with Will about how many pitches Hudson throws. He reckoned four (fast, splitter, sinker, change) but I had read he threw the slider too. Although the data aren't 100% conclusive as identifying the pitches is more of an art than a science I reckon he does throw the slider on occasion. Take a look at the article, see what you think, and let me know.