Defensive Projections

Here they are for 2008. I projected every outfielder with two ratings, one as a right/left fielder and one as a center fielder. Infielders get a projection for every position they actually played.

Projections are based on 4 years of data, age adjusted, and regressed to the mean. I've changed a few things about regression to the mean - outfielders are regressed to a mean that is a function of their speed score. A thanks to Mitchel Lichtman for opening my eyes to something that should have been obvious through this article.

For infielders, all first and second basemen are regressed to a mean of zero. Shortstops and third basemen are regressed to a lower mean, with the regression target rising depending on playing time. Once a player has the equivalent of a full season of playing time at a position, the mean he is regressed to rises to zero. A shortstop who played only 5 innings or so would have a projection around -7.

The reason I do this is this: Let's say Miguel Cabrera, a bad defender at third, was forced to play a few innings of shortstop and missed a play or two. His projection, had I done nothing, would be about -1. Orlando Cabrera's projection is -1, and it should be obvious that they are not equals. If you can play every day at short and be only -1 runs compared to the best fielders around, you are pretty valuable. So I came up with this trick to force a below average rating to people who really don't belong at a position.

For outfielders, both ratings are determined by outfield games played at all three positions. For infielders, ratings at each position are calculated independently - Maicer Izturis's shortstop rating is based only on his time there and has nothing to do with what he does at third base. Infield ratings are just based on a player's 4 year weighted record, playing time, and age.

The Ratings can be found here.