AaronGleeman.com

First, a few definitions ...

Okay, now that we have those out of the way, here are some shortstop numbers:

SHORTSTOP             ZR      RF     FLD%     IN/DP
Jason Bartlett      .831    4.24     .960      17.2
Juan Castro         .791    5.13     .991      13.6
Cristian Guzman     .823    4.65     .983      12.7

Cristian Guzman's stats are from last season with the Twins, while Jason Bartlett's and Juan Castro's numbers are from this season. Also, Castro's numbers are only from his time at shortstop, not from second base or third base.

If the above is to be believed, Castro has had more chances than either Guzman or Bartlett (which is often due to the pitchers on the mound), while Bartlett has been the best of the three at getting to balls in his zone, but the worst of the three at committing errors and turning double plays. Those stats do make some sense in Bartlett's case.

I thought Bartlett's range was pretty great, as he got to several balls that I felt Guzman never would have come close to. At the same time, he booted more than his share of fairly routine plays and wasn't great turning two, both of which are reflected in the numbers. Of course, if you buy into all that you also have to buy into Castro fielding a lower percentage of balls in his zone than Guzman did, which is a tough sell on me.

Now let's look at some third base numbers:

THIRD BASE            ZR      RF     FLD%     IN/DP
Michael Cuddyer     .752    2.74     .921      42.3
Corey Koskie        .779    2.56     .963      71.7

Again, Corey Koskie's numbers are from last season with the Twins, while Michael Cuddyer's numbers are from this season and only from his time at third base.

These numbers are a little more straightforward. Basically, Cuddyer has had more chances at third base than Koskie did last season, but has made a lower percentage of the plays on balls in his zone and has committed more errors. All of those things match up with what my eyes tell me, although that doesn't really make the stats any more or less likely to be "true."

Let's move over to second base:

SECOND BASE           ZR      RF     FLD%     IN/DP
Nick Punto          .889    4.99     .992      16.1
Luis Rivas          .839    4.61    1.000      13.4

Punto has had more chances than Luis Rivas and he's fielded a higher percentage of the balls in his zone than Rivas. Their fielding percentages are both nearly perfect, as Punto has the lone error in 426.2 innings between them, and Rivas has turned slightly more double plays per inning. Like with Cuddyer and Koskie, those numbers -- from Punto making more plays and showing more range to Rivas still turning a great double play -- match up with what my eyes tell me.

And finally, here are the percentage of balls in play that the Twins, as a team, have converted into outs:

YEAR      DER
2001     .700
2002     .705
2003     .701
2004     .688
2005     .711

Again, if those numbers are to be believed, the Twins' defense has been pretty damn good this season. Their DER ranks fourth in the AL and is better than in any of the past four seasons. Now, a pitching staff plays a role in a team's DER (although how big a role is the subject of much debate), and Twins pitchers have allowed the third-lowest percentage of line drives in the league this year.

In my mind, the Twins are better defensively at second base and shortstop, but worse at third base. They are also likely worse at first base, but a) first base is almost impossible to judge based on basic defensive numbers, and b) Justin Morneau played about half the season there in 2004. Catcher and the three outfield spots should be pretty similar to last year, so the swap of pluses at second and short and a minus at third might just be why the DER is up a tick.

UPDATE: I couldn't find mainstream confirmation of any of the moves as of midnight, but the Twins have reportedly placed Rivas on the 15-day disabled list, optioned Terry Tiffee to Triple-A, and called up Michael Ryan and Brent Abernathy. Personally, I think sending Rivas to Triple-A would have sent a bigger, better message, unless of course he's actually hurt.

In general though, these four moves probably have as small an impact on a baseball team as four moves could possibly have. The Twins lose a little defensive versatility by swapping Tiffee for Ryan as their lefty pinch-hitter, but they are equally mediocre offensively and Tiffee had played himself out of any meaningful playing time at third base anyway. As I've written here a number of times, Abernathy is a solid backup infielder and he certainly deserves a look after hitting .328/.394/.520 at Rochester.

Today at The Hardball Times:
- Disappearing Numbers (by Aaron Gleeman)
- Business of Baseball Report (by Brian Borawski)