John Dewan may have just figured out how valuable defense is

If you subscribe to John Dewan’s Stat of the Week, you may have read this already, in which case I apologize. But this is kind of a big deal; Dewan calls it the most significant discovery of his career. That’s a pretty bold statement for the guy whose +/- system is the basis for the freakin’ Bible (of defense).

Unfortunately, it took the 2008 Royals defensive suckitude to lead him to this revelation, but here we go (emphasis mine):

The worst defensive team in baseball in 2008? The
Kansas City Royals. Their defense cost them about 48 runs relative to
the average team. Comparing the Phillies and the Royals, the difference
between the best and worst defensive teams in baseball was about 130
runs.

Now, remember that number. 130.

The best run-scoring team in baseball was the Texas
Rangers with 901 runs in 2008. The San Diego Padres were the worst with
637 runs. That’s a difference of about 260 runs.

Here’s the discovery, and I found it because the
numbers just jumped out. The 130 difference in runs saved on defense is
exactly half of the 260 difference in runs scored. That’s exactly half.
The implication is that defense is worth about half as much as offense.
(Used with permission from John Dewan’s Stat of the Week™, www.statoftheweek.com.)

Dewan goes on to say that of course, this isn’t perfect, but the numbers bear him out a bit. (I can’t get the table he gives to format well in this post, but you can click the link above to see them for yourself.)

This is amazing – to have some sort of baseline to measure defense against; another way to look at a good defender with a bad bat and try to justify his roster spot. Or to look at a team that’s supposed to be built on defense but maybe still can’t win. Or really, to look at anything.

I’m not enough of a computer-headed baseball hater (my new favorite “insult” for stat-geeks) to know exactly how big the repercussions will be from Dewan’s realization. Maybe someone else has already noticed this, and I am just not “in the know” enough to have seen it. But it’s interesting all the same.

Related posts:

1. In defense of defense
2. A look at double play turning, from FanGraphs