Batting the Pitcher 8th

So there has been some recent talk about the utility of doing this. Some people criticized Bobby for not being more open to it (which would seem to indicate you're criticizing every single manager outside of Tony LaRussa, which is odd to me to say the least).

A lot of statheads really push it, saying you'll score around 2 tenths of a run more per game. I've looked at the stats and I think there is some validity to wanting to bat your worst hitter 8th. You want your best overall hitter (slugging and OBP) to bat third (that's another subject in itself), so you want to get one more high OBP/low slugging guy 9th so that when the order flips around in later innings he has even more RBI chances. That's a little oversimplified, but the basic gist of it. If you look at AL lineups these days, typically the worst overall hitter does hit 8th now. You'll have a good OBP/speed guy with no power batting ninth. But why, when it comes to the NL, does the pitcher always bat 9th? A couple of reasons:

1) In the NL, you want to protect your #7 hitter. If you bat the pitcher 8th, your #7 hitter, which on good teams is typically a pretty good hitter, is going to get pitched around even mroe than he already does. The stats really only look at OBP and Slug as a given, they don't observe how slugging is affected based on a pitcher hitting behind him. In the AL there isn't nearly as much difference between your 8th and 9th hitter, so this effect isn't as noticeable there.

2) In the NL you want your pitcher to have to bat as little as possible. The pitcher's only responsibility is pitching, if you can avoid a few ABs for him so that he is less gassed on the mound, you want to do that. It also means that you have a tiny bit more flexibility when it comes to when to take him out later in games, since he is less likely to come up.

3) the stats don't take bunting into account. Since the stats that say batting your worst hitter 8th are based pretty much purely on OBP and Slug, it doesn't take into account that probably the most important contribution a pitcher makes to the offense is bunting a guy over for the top of the lineup. You wouldn't want the pitcher bunting a guy over when two high OBP/low slug guys are coming up back to back after him.

Do those effects counterbalance the .2 runs that the statistics predict you would gain by batting the pitcher 8th? Hard to say. I'd guess it is pretty close one way or another (maybe .05 runs per game). I don't think either position is as crazy as the other side makes it out to be. With it not being obvious one way or another, I feel more comfortable keeping with tradition and waiting for some other NL manager to do it enough for a statistically valid study to sort it all out.