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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



  1. NMR says:

    Incredibly cool stuff, Travis. Thanks for the link.
    Should be interesting to see if teams will finally start paying players for their defensive value as much as their offensive value. And if not, whether the smart ones will use this to their advantage.

  2. Jim S. says:

    Great stuff, Travis. I’m guessing Dan Fox and the Bucs will be out in front of this new technology. I’ve been waiting for some sort of a system for years that actually tracks how far an outfielder travels to catch balls, on average. Knowing the trajectory and velocity of those balls, and how quickly he reacts will be terrific. I assume it will have a similar effect on our ability to judge the range of infielders.

  3. Nate83 says:

    I think the smart ones are already using it to their advantage. I think Martin being signed by the Pirates had more to do with his defense then anything else. I also think other teams not valueing that side of things as much made him available to the Pirates.

  4. NMR says:

    Certainly seems that way, Nate. I love how Tampa goes after not only defensive players, but versatile ones.

  5. NMR says:

    Gonna be interesting to see how different entities present this stuff to the public (if at all).
    The shear volume of aggregate data will be impossibly large for the layman like you and I to process, at least in terms of player comparisons and rankings. Metrics will have to be developed (or improved) in order to analyze this info in useable terms. Seems like people will either have to get comfortable with new stats or continue to bury their heads in the sand and reduce it to a bunch of nerds in their moms basement.

  6. Nate83 says:

    They have been doing it for years now. I really respect Madden a lot. His post game press conferences are very interesting to watch. He seemed to be on an island as far as his philosophies a couple years ago but recently other managers (especially small market) have been open to implementing some of his ways. It would be interesting to see how he would manage an NL team.

  7. RobertoForever says:

    I can’t believe there wasn’t one gold glove in there for the Bucs. I look forward to the day that Pirates positive reputation influences awards for them.

    And hopefully, Travis, you will be able to have access to the new data and provide your great analysis here.

  8. Jim S. says:

    Yep, the head-in-sand guys will be the usual suspects around MLB. I think the Bucs will eat this stuff up with a spoon, and will have their team of “numbers geeks” (said affectionately) dissecting it into a usable form for NH and CH pretty quickly.

    Incidentally, I don’t know if anyone heard this after the game last night, but I about choked when I heard Gomes reference WAR in an interview after the game. I don’t even recall the context, but I found it amazing. Then, this morning, I read a tweet referencing Gomes. I think it was Tim Williams. His point was to pay tribute to Bill James for how he has affected baseball and how we all look at it. And, it isn’t just us SABR advocates now. Everyone in MLB, including the oldest, crustiest, staunchest detractors of SABR stuff, use some of these analytics in their jobs. I was pretty young when I started reading the old Bill James Baseball Abstracts, but it blew my mind at the time. He, and guys like him, were true pioneers. I know I would not enjoy baseball half as much now without being introduced to this new way of looking at things over 20 years ago.

  9. Jim S. says:

    Some of the things Gomez did in CF this year for Milwaukee, including bringing back 5 HRs, probably meant that he deserved the GG a tad more than Cutch. But, Marte and Martin? Marte should have won in a landslide. And, if Martin can’t beat Yadi now, when can he beat him?

    The point you brought up about reputation is so valid Roberto. If you watched much of the series, you could not go more than an inning without Buck and McCarver marveling over Molina. In fact, it went on for the entire playoffs. I know the guy is a great catcher, but he made a bunch of bad plays over these 3 series’ that I can recall off the top of my head. He dropped a popup in Game 2 in the Bucs series. Costas and Kaat immediately covered for him, and said how great he is. Did you see the play at the plate with Big Papi? I think it was Game 4 or 5. Molina was positioned on the foul side of the line. The ball was thrown perfectly right inside the line, where he should have been, and he had no chance to catch or tag Papi on a close play. He also allowed a pop to drop, along with Wainwright in Game 1, I think. Finally, last night, on Victorino’s 3 run double, he turned to argue with the ump while the ball was still in play. Victorino continued right to 3rd, and nothing was ever said. At one point last night, McCarver mentioned that Molina had 0 pick-offs this year. Did he see it as a sign of him slipping? No, it means he is so feared that guys don’t venture off the bases now against him, according to McCarver. Talk about reading whatever you want into the numbers. Can you tell I thought Martin had a better defensive year? Yadi is still great. I know that. But, he was not at his best in this playoff season.

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