Fun with Matchups

Question: How often do particular hitters face paritcular pitchers in a season?

To answer that question I took a look at matchup data for 2003 through 2005. The following list are those hitters with the most at bats against a particular pitchers over that time period.

I've also included the hitter's average over the period, the pitcher's average against as well as the expected average for the matchup based on the log5 method that Bill James published in the 1983 Baseball Abstract. Dan Levitt has written a nice article on the formula and its accurracy.

So from the table you can see that around 15-20 at bats per season are probably the max.

Batter              Pitcher               AB       H     AVG    BAVG    PAVG   ExAVg
Garret Anderson     Jamie Moyer           45      10   0.222   0.300   0.267   0.300
Juan Pierre         Livan Hernandez       43      13   0.302   0.303   0.262   0.297
Carl Crawford       Tim Wakefield         42      15   0.357   0.293   0.251   0.277
Michael Young       Barry Zito            41       9   0.220   0.317   0.234   0.281
Ray Durham          Brian Lawrence        41      14   0.341   0.286   0.272   0.292
Angel Berroa        Mike Maroth           41      15   0.366   0.273   0.292   0.299
Derek Jeter         Tim Wakefield         40       9   0.225   0.307   0.251   0.291
Garret Anderson     Ryan Franklin         40      13   0.325   0.300   0.272   0.306
Ichiro Suzuki       Barry Zito            40      14   0.350   0.330   0.234   0.293
Derek Jeter         Rodrigo Lopez         40      19   0.475   0.307   0.279   0.321
Miguel Cabrera      Livan Hernandez       39       8   0.205   0.300   0.262   0.295
Jimmy Rollins       Dontrelle Willis      39       9   0.231   0.281   0.254   0.268
Manny Ramirez       Rodrigo Lopez         39      12   0.308   0.309   0.279   0.323
Juan Encarnacion    Livan Hernandez       39      15   0.385   0.265   0.262   0.260
Ray Durham          Jake Peavy            38       6   0.158   0.286   0.230   0.248
Luis Castillo       Livan Hernandez       38       9   0.237   0.302   0.262   0.297
Manny Ramirez       Roy Halladay          38       9   0.237   0.309   0.248   0.288
Juan Pierre         Tom Glavine           38      11   0.289   0.303   0.272   0.309
Luis Gonzalez       Jason Schmidt         38       8   0.211   0.280   0.214   0.226
Torii Hunter        Mark Buehrle          38      11   0.289   0.262   0.271   0.266
Michael Young       John Lackey           38      15   0.395   0.317   0.271   0.322
David Ortiz         Roy Halladay          38      14   0.368   0.297   0.248   0.277
Mark Kotsay         Ryan Franklin         37       9   0.243   0.288   0.272   0.294
Cesar Izturis       Brett Tomko           37       9   0.243   0.267   0.281   0.282
Johnny Damon        Roy Halladay          37      13   0.351   0.298   0.248   0.278
Carl Crawford       Josh Towers           37      15   0.405   0.293   0.290   0.317
Eric Chavez         Kenny Rogers          36       7   0.194   0.275   0.285   0.295
Ichiro Suzuki       John Lackey           36      11   0.306   0.330   0.271   0.335
Johnny Damon        Rodrigo Lopez         36      11   0.306   0.298   0.279   0.312
Michael Young       Joel Pineiro          36      13   0.361   0.317   0.268   0.319
Eric Chavez         Ryan Franklin         36      12   0.333   0.275   0.272   0.281
Derek Jeter         Sidney Ponson         36      16   0.444   0.307   0.294   0.336
Hank Blalock        Joel Pineiro          35       5   0.143   0.279   0.268   0.281
Hideki Matsui       Tim Wakefield         35       6   0.171   0.297   0.251   0.281
Cesar Izturis       Adam Eaton            35       8   0.229   0.267   0.261   0.262
Michael Young       Bartolo Colon         35      11   0.314   0.317   0.255   0.304
Shannon Stewart     Jake Westbrook        35      11   0.314   0.294   0.265   0.293
Juan Pierre         Mike Hampton          35      12   0.343   0.303   0.273   0.310
Alex Cintron        Jason Schmidt         35       9   0.257   0.283   0.214   0.229
Shawn Green         Jake Peavy            35      10   0.286   0.277   0.230   0.240
Jacque Jones        Jon Garland           35      12   0.343   0.268   0.262   0.264
Lew Ford            Mark Buehrle          35      13   0.371   0.285   0.271   0.289
Brad Wilkerson      Tom Glavine           35      14   0.400   0.257   0.272   0.262