The Daily Prospectus: Interleague Time

by Joe Sheehan

With interleague play opening today, Keith Woolner assembled some data on how pitchers and DHs have done over the four seasons of cross-circuit play. There's some fun stuff here, so I figured I'd pass it along:

As you'd expect, The National League's pitchers have hit better in IL play, with a .150/.169/.196 line over the four years, to the AL's .128/.155/.167. Personally, I thought the gap would be greater, but:

  • NL pitchers don't hit much in the minors either, and
  • there's enough player movement that many AL hurlers have batted for NL teams

NL pitchers have gotten a lot more PAs in IL play, nearly 1,000 more in the four seasons. I would have thought that the effect of being the home team would cause the opposite to be the case—an NL pitcher coming up would have already pitched the top half, and might be more likely to be pinch-hit for—but this is clearly canceled by the AL's greater willingness to hit for its pitchers.

NL pitchers lay down sacrifice bunts more often than their AL counterparts, with 342 successful sacrifices in 3226 PA (10.6%). The AL's numbers? 215 in 2297 PA (9.4%). I don't have information on failed sacrifices, but that's probably most of the difference, because there are virtually no AL pitchers allowed to swing away in a sacrifice situation, whereas there are a handful of NL pitchers who are.

The advantage the NL has when their pitchers are at the plate is given back, and then some, by their DHs, although the gap has shortened of late:

             PA    AVG    OBP    SLG 1998 AL    532   .290   .374   .434 1998 NL    492   .221   .287   .337  1999 AL    581   .264   .356   .425 1999 NL    574   .255   .343   .395  2000 AL    596   .353   .448   .598 2000 NL    556   .288   .372   .422  2001 AL    519   .274   .347   .460 2001 NL    508   .261   .341   .420

That AL spike in 2000 is something. I'm guessing that was part Frank Thomas, who had his only good year in the IL play era that season. Brad Fullmer was a full-time DH in his big year…I believe that was Rafael Palmeiro's DH season (in which he won the Gold Glove).

It seems that NL managers have gotten better about adding players to the roster for interleague play who can actually give them some help. NL DH numbers are also inflated by the at-bats given to players like Mike Piazza, as a day at DH can provide 80% of the benefits of an off day while keeping a productive bat in the lineup.

What I think is fun is where the NL is hitting its DHs:

 Lineup spot      1998  1999  2000  1                  35    51    14 2                  45    25    11 3                  29   150    69 4                 103    77    69 5                  86    80    99 6                  66    81   177 7                  92    77    60 8                  24    25    44 9                  12     8    13

I have to say that I get a kick out of the fact that 3-5 times a year, an NL team bats its DH ninth. Through 2000 (sorry, that's all I have), NL teams seem to have settled on using the DH to get some power in the middle of the lineup. Sometimes, they'd move a regular to the spot—that's what accounts for most of the 3-4-5 appearances, and the spike in the #3 hole in 1999—but, in 2000, in particular, they were finally coming around to the initial idea of a DH: a chance to stick an extra quality bat in the lineup.

Thanks again to Keith Woolner for his work on this piece. Have a great weekend, everyone!

Joe Sheehan is an author of Baseball Prospectus. You can contact him by clicking here.