Baseball Info Solutions sent me their fielding data, and that means it's time to start presenting the 2008 Probabilistic Model of Range. If you're new to this, you can find explanations in this archive. Basically, for each fieldable (non inside the park home runs) ball put in play, six parameters are used to determine how difficult it was to field the ball. A probability of turning the ball into an out is calculated, and those probabilities are summed. That gives us expected batted balls turned into outs. We turn that into a predicted DER (defensive efficiency record), compare that to the actual DER and calculate a ranking.

The model is based primarily on visiting player data, smoothed, using distance on fly balls and a hard hit indicator on ground balls. Only 2008 data was used to construct the model.

Note that a team can post a poor DER during the season, but do well in this model if the balls put into play were extremely difficult to field. This helps the Braves rank second.

The Rays turned in the best combination of good pitching and good defense. Their .699 predicted DER was second to the Mets. Unlike the Mets, however, the Rays fielded more balls than expected, giving the best DER, but only the third best Index. The Blue Jays turned in a tremendous defensive season, a big reason their pitching staff did so well in ERA in 2008.

The bottom of this chart is very interesting. From the Padres down, teams 23-30 all turned out to be very poor teams with the exception of the Yankees. Defense didn't necessarily help a team win, as the Phillies were pretty middle of the road, but it certainly seemed to indicate a pretty bad team.

Note that last season, the Devil Rays were at the very bottom of the list. They improved both their predicted DER and their ability to turn batted balls into outs. That was enough to lower their runs allowed from 944 to 671 and make them American League champions.