How much do we really know about defensive value? And why we might have a better understanding soon


LEBO – Carlos Gomez was a deserving Gold Glove winner in center field. He led baseball with 38 Defensive Runs Saved in 2013 and had five home run takeaways. Whether using your eyes or advanced stats, he was sensational. I don’t think Andrew McCutchen, as good as he is in center, was robbed of his second straight Gold Glove.


You can argue that Starling Marte and Russell Martin were robbed of Gold Gloves.


Martin and Marte out-produced GG winners Yadier Molina and Carlos Gonzalez according to a number of new-age defensive metrics. But even with a SABR-chosen sabermetric panel making up 30 percent of the vote for the first time, the Molina and Gonzalez brand names were perhaps too much to overcome.


We might soon have a better understanding of who should win these awards 


But here’s the thing: we still really don’t know who the best defenders in baseball are and what their real values are. Yes, through the eye test we know Andrelton Simmons is really, really good. But the eye test can be misleading as can the new-age stats, which even sabermetric types admit are far from perfect.


But there is a new technology that is becoming available which will revolutionize our understanding of defense.


Over the last two seasons Sportsvision, the company which brought us Pitchf /x, which aided greatly in our understanding of pitching and pitch types, has begun installing Field f/x into major league stadiums.


Like Pitch f/x, Field f/x will track the trajectory and velocity of batted balls. It will track the range of players, their quickness, their reaction times and arm strength. (More reading on Field f/x here in this WSJ piece).  It’s fascinating stuff, something that seems more out of NORAD or science fiction than baseball.


In short, for the first time we will understand the value of individual defenders.


Pirates’ data whiz Dan Fox is excited about it. This from Fox told me this summer:


“Hopefully over the next couple of years it is installed everywhere and we’ll get millions of data points per game and it will be awesome,” Fox said. “With defense we take the idea that any system we devise with the current kind of data we have is going to be imperfect so we favor the more the better. You are not measuring it directly you are valuing it, because, you are not measuring first-step quickness or arm strength until you get things like Field f/x.”


While it’s not immediately known if Field f/x will be made available to the public like Pitch f/x data, the industry will have a much better handle on who are really the best defenders in the game and what the defense is worth. It’s pretty exciting stuff.


And perhaps for the first time the Gold Glove awards can become based upon something more than just an eye test or imperfect sabermetrics.


– TS