Atlanta Braves feature 9 defenders on midyear SABR Defensive Index

SABR just released its midyear Defensive Index (SDI™) showing six Braves’ players in the top 25 overall ranked players on the list.

SDI’s ranking also lists Atlanta Braves players among the top ten in 8 of the 9 individual categories.

According to the website linked above, six years ago SABR joined the team providing data to writers selecting winners of both the Rawlings Gold Glove and Rawlings Platinum Glove Award™, presented by SABR.

The SDI itself accounts for about 25% of the selection process that also includes votes from managers and coaches. Voters receive SDI data along with their ballots to add statistical insight to their personal observations.

Explaining the SDI

Rawlings asked SABR to come up with “a single measure of a player’s defensive performance” as a way of combining and simplifying advanced metrics for use by voters.

The SABR committee created to accomplish the task from two types of metric to create SDI.

1. Batted-ball and location-based data
2. Data from play-by-play accounts.

They chose defensive runs saved (DRS), ultimate zone rating (UZR) and runs effectively defended (RED) based on STATS Zone Rating for batted-ball data, and agreed on defensive regression analysis (DRA) and Total Zone Rating (TZ) for play-by-play data.

"The SDI algorithm includes three measures based on zone metrics. . .which account for 70% of the SDI value; and two measures based on play-by-play data. . .which account for 30% of the SDI value."

I downloaded the spreadsheet used for the 2013 process – you can as well by clicking here – to look at the way they structured to formulas.

The committee created a separate formula for pitchers, catchers, and fielders that generally gives DRS and RED the most weight with TZ and DRA rated equally ranked when used.

They also adjusted the pitcher and catcher formula to make them comparable to the fielders.  If you’re curious about the actual weights and adjustments download the spreadsheet.

While the process may evolve, the formula remains unchanged for this season.

Where the Atlanta Braves rank

When Alex Anthopoulos took over he said his focus would be on improving the defense. So far this season the eye test backs that up.

One position does, however, appear in need of significant improvement.

I’m a fan of getting Mike and Sean learning to land in a better fielding position but teams today seem to place little emphasis on that. The only real problem area is catching.