Chris Snow in the Globe had a good article a couple of days back on how changing leagues can affect pitchers. Brought up a good point from Bill James that while pitchers tend to do well upon changing leagues, you can’t attribute that purely to the well-known fact that the senior circuit is easier to pitch in thanks to the pitcher having to bat, but also to the fact that pitchers tend to switch leagues after poor seasons:
“Pitchers tend to switch leagues after a poor season,” said Bill James, senior baseball operations advisor for the Sox and author of the annual Bill James Handbook. “Derek Lowe going to Los Angeles now, rather than after his 2002 season. This creates a ‘weighted’ sample, which tends to weight the data in a way you might not anticipate.”
Still, for the big signings this off-season, I foresee good things happening to the big AL-to-NL movers (Pedro, Hudson, Mulder, Lowe - all of who came off weak seasons), and general weakness for the big NL-to-AL ones (Clement, Pavano, Jaret Wright). (I’m clearly missing a few on that list, thanks to my head being filled solely with visions of the Mariano Rivera Face.)
Speaking of the Mariano Rivera Face, seems like a bad start for many closers - Looper, Wickman, Takatsu… even Foulke took the L in Game 2.