Many aspects of the 2008 Milwaukee Brewers are different from that of the '07 club, but the one that may end up having the biggest impact on the bottom line is the defensive realignment.  Since we have a day off (it's like a gift of three hours back in my life!) I thought I'd look at the issue from a variety of angles.

First, let's just think about what we've seen.  Four of the eight defensive positions are manned by the same folks who played there last year.  Of those, Hardy is solid, Hart is probably average with a plus arm, while Prince and Rickie are below average.  The only real change from last year is that I think Rickie is a little better--still making spectacular plays, still making mistakes on relatively easy plays, but doing the good things more often and the bad things less often.

The other four spots are big changes:

• Catcher: Kendall appears to be a huge improvement.  Maybe he'll stop being effective gunning down runners, but I can't even imagine anyone arguing that Kendall isn't a net plus in the field over Estrada.
• Third base: Bill Hall looks great.  I don't know whether he'll turn out to be above average, but if he's average, that's a massive gain over last year.
• Left field: I'm not sold on Braun being all that good, or even having the potential to be all that good out there, but at the same time, he's clearly not all that bad.  It isn't like sticking Jack Cust or Manny out there.  Regardless, it's a step down from Jenkins, and probably a big one, but not enough to offset the advantage of getting Braun off of third.
• Center field: I really wanted Hall to succeed in center last year, but it's pretty clear that he didn't.  We've already had three center fielders this year who looked better than Hall did at the position, and Mike Cameron hasn't played an inning yet.  This is a step up, and it's likely to get bigger.

Of course, you knew I wasn't going to stop there.  25 games is not really enough to do any serious statistical analysis of defense, but let's see what the numbers say anyway.

A good starting point for team defense is defensive efficiency, which is the fraction of batted balls that turn into outs.  Last year, the Brewers had a DefEff of .674, 14th out of 16 NL teams.  (Only the Rats and Fish were worse.)  This year we're at .711, 6th in the league.  You can always find DefEff in the "Miscellaneous Stats" section of Baseball-Reference's league pages .

Just doing some back-of-the-envelope calculations, I think that every .001 of DefEff is worth about 3 runs.  (I'm figuring .001 represents about 5 more batted balls turned into outs; if they are all fly balls, it's more like 4 or 5 runs; if they are grounders, it's 2-2.5.)  Viewed in this light, a DefEff increase of .037 would be astonishing: that's an improvement of over 100 runs, or about 10 wins.

That probably won't hold up over the course of the season, but even half that would be impressive.  It could also be partially attributable to the pitching, if they get more ground balls and infield flies.

Another place to look for defense indicators is the new-for-2008 Hardball Times Team Page.  Here are some of the things we can glean from today's report (it's updated daily):

• A fielding plus/minus of -1 suggests that we're about average.  I'll take it.
• We're near the bottom in RZR (the percent of "in zone" balls that are successfully fielded), but second best in the league at getting outs on balls out of zone.  That seems plausible to me: There have been plenty of great plays so far, but still our share of missed opportunities.
• The infield/outfield split is dramatic.  We're near the bottom as an infield, but 5th best as an outfield.  Cameron's return may help that go even higher.
• We're nearly best in the league in errors, and by far the best in the league in unearned runs.  (Since unearned runs are based in large part on errors, it's no surprise that those two go hand in hand.)  If you haven't noticed by now, I don't put a lot of stock in traditional fielding metrics such as errors and fielding percentage, because they are based on the subjective judgments of scorers.

That's probably enough for today.  It'll take many more games before we can make any kind of confident assessment of team defense this year, but even if we go with the more pessimistic view (represented by RZR), that the Brewers are roughly an average defensive team, that's a huge score for the good guys.  It's a testament to Melvin's offseason juggling, as well as the flexibility of Bill Hall and Ryan Braun.