Since its 1957 inception, the Rawlings Gold Glove Award has been a welcome addition to Major League Baseball’s annual recognition process, while also being a source of controversy at times. Those considered to be the best defensive players by position by league are selected annually via a vote of MLB managers and coaches.
Despite this seemingly-knowledgeable voting constituency, there have been a number of questionable winners over the years. Perhaps most notable was the selection of Rafael Palmeiro following a season in which he was almost exclusively a designated hitter.
In fact, the difficulty of separating hitting from defense has been perhaps the award's greatest challenge over time. It has seemed that to win a Gold Glove, one must also have a good season with the bat, and if not, the chance of winning the top defensive award is dramatically decreased.
Recognizing that a lack of readily-available defensive metrics may be one reason offense is being overly considered, Rawlings and the Society of American Baseball Research (SABR) established a partnership. The idea was to bring in an impartial party to adjust the existing process rather than scrap it entirely.
A committee of seven sabermetric experts was convened to study the issue and developed what they call the SABR Defensive Index, or SDI. At its essence, the SDI is expressed by the number of runs a fielder "saves" his team.
By definition, the construction of the SDI is complicated, however, as it takes into account information from a number of sources - from batted ball, location-based data (70 percent weighting) and from play-by-play accounts (30 percent). The three metrics representing batted ball data include Defensive Runs Saved from Baseball Info Solutions, Ultimate Zone Rating developed by Mitchel Lichtman, and Runs Effectively Defended built by SABR member Chris Dial. The two metrics from play-by-play data are Defensive Regression Analysis, created by Michael Humphreys, and Total Zone Rating.
What these fielding metrics capture include a fielder's range, throwing arm, sure-handedness, ability to turn double plays, ability to convert bunts into outs, scoops of throws in the dirt as well as the number of "excellent" and "poor" fielding plays.
For outfielders, the ability to prevent runners from taking an extra base is rated. For catchers, blocking balls in the dirt and stolen bases/caught stealing are also included. A pitcher’s ability to control the running game by holding runners on base is also measured.
In terms of Gold Glove Award weighting, the SDI will be worth 30 total "votes.” That represents approximately 25 percent of the scoring, which will be added to the traditional votes from the managers and coaches.
SDI results will also be provided up front to help the voters. A statistical resource guide will accompany the Gold Glove Award ballots sent to managers and coaches. Whether or not they actually use it remains to be seen.
The 2013 Rawlings Gold Glove Award winners will be announced on October 29 – the first time we will see if including sabermetric defensive stats leads to a better set of winners.
The SDI will also be used in comparing players across positions to help determine the updated Rawlings Platinum Glove Award, for the single best Gold Glove Award winner.
At this point, the Platinum Glove Award voting process has not yet been announced, but the online fan vote will continue once the Gold Glove Award winners are revealed. As such, the SDI will be shared with the general public, as well. That could go a long way toward potentially increasing its acceptance by a broader cross-section of baseball observers.
In the bigger picture, perhaps if defensive metrics can be more standardized and are embraced by the baseball community as a whole over time, fantasy baseball could also incorporate a defensive component.
The SDI potentially represents a step in that direction, and for that reason, I hope it is successful.
Brian Walton was the 2009 National League Tout Wars champion, scoring the most points in the league’s 14-year history. Though he is the only one to remember or care, he also finished second in each of the two subsequent seasons. His work can also be found daily at TheCardinalNation.com and thecardinalnationblog.com. Follow Brian on Twitter.