THE BOOK--Playing The Percentages In Baseball

I hadn’t realized MLB changed rules for the bats.

Depending on the magnitude of these changes, shouldn’t this be mentioned as a *possible* contributor to the lower offensive numbers we’re seeing?

The “slope of grain” rule was instituted starting with the 2009 season.  I was not aware of the new rule this year in which new MLB players are not allowed to use “low density maple bats”.  Not sure what low density means.  Maple has a higher density than mountain ash, the other primary material used for MLB bats.  In any case, there have been studies of the relative effectiveness of maple and ash bats and they have been found to perform the same.  I think the reason batters have migrated toward maple in recent years is that maple does not “flake” and, in principle, is more durable than ash. 

To learn more than you ever want to know about these things, see http://www.woodbat.org/.

Alan, is there any reason to think the slope of grain requirement could impact HR and BABIP rates?

Guy:  No reason to believe these things are affected by the slope of grain requirement.

Sweet.  I never thought my former employer would end up being so helpful to my favorite sport.  I’m wearing my (slightly stolen) Forest Service belt buckle with an extra amount of pride today.