As I mentioned a few days ago, I've been preparing some 2010 league averages for many of the stats I use here. Glossary is below ...

League | # | Swing | Whiff | Zone | Chase | Watch | Called | Z-Whiff | O-Whiff | Foul | A/B | Pace |

AL | 326,368 | .454 | .199 | .449 | .302 | .360 | .325 | .132 | .315 | .378 | 1.95 | 20.8 |

NL | 375,074 | .453 | .216 | .441 | .303 | .355 | .328 | .142 | .342 | .369 | 1.96 | 20.9 |

MLB | 701,442 | .454 | .208 | .445 | .302 | .358 | .327 | .137 | .329 | .373 | 1.95 | 20.8 |

League | GB Rate | FB Rate | LD Rate | PU Rate | HR/FB | wOBAcon |

AL | .442 | .294 | .186 | .077 | .107 | .352 |

NL | .456 | .282 | .191 | .071 | .110 | .353 |

MLB | .450 | .288 | .189 | .074 | .109 | .353 |

League | K Rate | Swinging K Rate | Looking K Rate | P/PA |

AL | .178 | .133 | .045 | 3.81 |

NL | .192 | .145 | .046 | 3.81 |

MLB | .185 | .139 | .046 | 3.81 |

I'll set up an "official" glossary page in a few days, but for the meantime, I'll define right here how the stats are calculated. Swing, zone, and whiff rates are three that I use a ton - swing rate is the percentage of pitches that a batter swings at, zone rate is the percentage of pitches that are seen inside the strike zone, and whiff rate is the total number of swinging strikes (whiffs, foul tips, missed bunts included) divided by the total number of swings. For the strike zone, I've been using a 17-inch plate plus 1.5 inches on either side to account for the width of the ball (thanks to Joe Lefkowitz for the methodology). Z-Whiff and O-Whiff are the whiff rates on pitches in the strike zone and out of the zone, respectively. Chase rate is the number of pitches a batter swings at out of the strike zone divided by the number of pitches out of the strike zone; watch rate is the number of pitches in the strike zone that a batter

*doesn't*swing at divided by the total number of pitches in the strike zone. A/B is something that I recently added to my data; it is the number of pitches for which a pitcher is ahead in the count (run expectancy < 0) divided by the number of pitches for which a pitcher is behind in the count (run expectancy > 0, excluding full counts, which I classify separately). Harry Pavlidis used a metric similar to this last year, though I believe he calculated it based on at-bats rather than individual pitches. The final column in the first table holds the metric that I'm quite possibly most excited about. Over the summer, I wrote about how I calculated the time between pitches and that I was testing it out on the Yankees' 2010 pitchers. Compared to Mike Fast's research in 2008, my numbers seemed to be reasonable, so I set up the pitch time stat (measured in seconds) for the pitchers on the 29 other teams. For now, the pitch times only include data with the bases empty, because I can't track pick-off throws. I've eliminated the first pitch of each plate appearance so that the time between PAs doesn't get counted; also, any set of pitches for which I receive less than a second or more than a minute have been discarded because they most likely indicate a PITCHf/x glitch or an on-field delay.

The second and third tables are probably more self-explanatory. The second is for batted ball data, showing ground ball rate, fly ball rate, line drive rate, and pop up rate. HR/FB fly ball home runs divided by outfield fly balls. wOBAcon is weighted on base average for non-foul contacted pitches. The third table shows some general plate appearance results - P/PA is pitches per plate appearance. The strikeout rates are based on strikeouts per total batters faced.

As always, the data here are courtesy of Joe Lefkowitz's PITCHf/x tool.

EDITED: 02/07/11, 03/15/11, 04/06/11

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