As introduced in John Dewan’s "The Fielding Bible -- Volume II," Baseball Info Solutions (BIS) analyzes eight aspects of defense and calculates the number of runs each fielder saves relative to others at his position. Brett Gardner currently leads baseball with 22 "Defensive Runs Saved," meaning that Baseball Info Solutions estimates that the Yankees would have allowed 22 more runs with an average left fielder in his place. Austin Jackson led baseball with 11 Defensive Runs Saved in the month of August, and his 17 Defensive Runs Saved this season is tied for third among all center fielders. Robinson Cano tied for the infield lead with 7 Runs Saved on the month.
Baseball Info Solutions also tracks "Good Fielding Plays," or GFP for short. A GFP is a Web Gem-type play where a fielder makes a play which records an unexpected out or prevents a runner from possibly advancing. A diving catch in the outfield is typically a GFP, but we also record a GFP when an outfielder cuts a ball off in the gap and gets it back to the infield, preventing potential advancement. BIS records 28 different GFP categories. Robinson Cano led baseball with an astounding 23 Good Fielding Plays to go with his 7 Runs Saved in August.
The natural opposite of a GFP is what we call a "Defensive Misplay," or DM. You can think of a DM as any play where the fielder does something identifiably wrong but for whatever reason isn’t charged with an error. A DM always has a negative consequence, either failing to get a potential out or allowing other runners to advance when they might have been held if the correct play had been made. We record Defensive Misplays when an outfielder dives but misses a flyball (turning a single into a double or a triple) or when an infielder fails to cover the base in time to get an out, along with 52 other categories of plays. We often group Defensive Misplays and errors together because they describe similar results, though the official scorer decided to call one an error and not the other. Cano made just three Defensive Misplays in August (along with just one error), which is a pretty remarkable month at second base.
We can use a combination of Defensive Runs Saved, Good Fielding Plays, and Defensive Misplays/errors to evaluate fielders through different lenses. Good Fielding Plays are often flashy and catch our eyes, but we need to compliment our observations with a system that can tell us everything we don’t always see, including the fielder’s pre-pitch positioning, his quick first step, or the bad route he took before he made that diving catch. That’s where Defensive Runs Saved provides a more complete and objective measure of a fielder’s impact.
Ben Jedlovec is a research analyst for Baseball Info Solutions. Follow him on Twitter @BenJedlovec.