When Bill James updated his Historical Baseball Abstract with Winshares in 2001, he felt comfortable about the offensive components but still was uneasy about defense. It’s very difficult to measure defensive skill and defensive value, and to make matters worse, skill and value are not necessarily related.
In researching the odd statistical variance between Bill Buckner and Steve Garvey, he hit upon a key element of defense which makes it difficult to quantify: discretion. Specifically he noticed that Buckner, who carried a weak defensive reputation racked up a ton of assists while Garvey, who owned four Gold Gloves, did not.
In the real world, this was a trivial distinction; all it really indicates is the preference of each player in making a certain play. Baseball players are taught from a young age that, when a ground ball is hit to the first baseman, it is the pitcher’s responsibility to cover first base. Buckner, in part because he had constant pain in his legs, was fanatic about insisting that pitchers do this. I can still see him in my mind’s eye, standing five feet from first base, fielding a slow-hit grounder with the glove on his right hand, pointing vigorously to the bag with his left hand, saying “Your play. Get over there. Cover the bag.” … If a pitcher failed to cover first, Buckner would immediately go to the mound and tell him about it.
Garvey, on the other hand, was paranoid about making unnecessary throws, and strongly preferred to make the play himself if he could. As Garvey saw it, why risk the throw when you can make the play yourself? In part, he saw it this way, no doubt, because he couldn’t throw; he was a fine first baseman, but he had no arm.
…Thus if you use assists by a first baseman to represent “range,” you will reach the conclusion that Buckner was a much better defensive first baseman than Garvey. … The problem with this is, it’s just not true. Buckner was not an outstanding first baseman, and Garvey was not a poor defensive first baseman. A hundred and twenty extra assists per season doesn’t really have any value to the team in this case, because it doesn’t refelct anything other than a choice.
For most of my high-school career, I played in left field next to a speedy center fielder and behind pitchers that often over powered their competition. I played more shallow and towards the line than a typical left fielder would play. I wasn’t fast, but I made good reads and got good jumps. The centerfielder had a better arm than I did, so if we converged on a ball with men on base, I let him make the catch. His skill-set in center let me get to foul balls and turn bloop singles into outs. I may not have made as many plays as I would have as an individual playing a more conventional depth, but as a team, we probably made more plays.
We’ve come a long way since 2001 with the defensive statistics. FanGraphs uses UZR and there’s Dewan’s Fielding Bible’s +/- system plus tons of other stuff is evolving all the time. Not to mention proprietary information hoarded by some, if not all, of the clubs. These systems are dogged and incredibly detailed. The most widely employed use the best information available to divide the field into buckets and to describe the kinds of balls hit into those buckets, and then to assign credits and debits for the plays that are made or not made. It’s a little dizzying, but if you want to read about all the hard work this entails, and how well-thought out the systems are, check here, here and here.
But baseball defense is a team defense, dynamic and shape shifting. It resists our attempts to assign individual debits and credits. The manager scatters his players over the field in whatever manner he thinks will prevent the most runs from being scored. During the course of play, he redeploys the fielders from batter to batter and situation to situation. The coaching staff’s ability to properly position the players – and the organization’s ability to scout opposing hitters effectively – directly impacts a player’s defensive statistics.
Beyond positioning, there are several plays in any game which may be made by more than one fielder. The fielder who catches the ball gets all the credit, the person who stands next to him gets none. That makes sense when you want to record the event for posterity, but it tells us absolutely nothing about the players’ skills nor his contributions to the team.
The best way to start defensive analysis is at the macro level. How did the team do at preventing runs? What was their defensive efficiency? And then assign credit amongst the players for the total accomplishment with the understanding that defense is a team-wide effort.
Right now, to decide the value of each player’s defensive contribution, we take a player’s runs saved or allowed and compare it to the average player at the same position in his league that year. This is not nearly as definitive a tally as it is for hitters. Take any hitter and compare him to the Major League average and you’re comparing him to 269 other lineup spots, and 170,000 other plate apearances. Compare Derek Jeter to the average American League shortstop, and you’re comparing him to only 13 other data points.
It’s no wonder a player can leap from ten runs below average to ten runs above average in a single season. With absolutely no change in skill or performance on the player’s part, or even with the expected decline in skill that accompanies age, an injury to an elite fielder or a change in positioning philosophy can swing the results dramatically.
Next we take those runs above or below average as if they were exaclty as reliable as our offensive runs calculated and mash them together to get an all-encompassing WAR. If a player is found to be nine runs below average on defense, he loses about a full unit of WAR. But does being nine calculated runs below average – whatever average that year happens to be given the radically shifting annual landscape – actually cost your team anything at all? I’m not confident the results are so precise.
I have no doubt that we’ll keep getting better at this. I have no doubt that there is useful information in what we already have. But I also have no doubt that current defensive statistics should not be used to decide someone’s MVP vote nor free agent contract amount. They should be evidence in favor or against a player, but in proper proportion to their inherent lack of reliability.
When Bill James discovered the flaw in the relative ratings of Buckner and Garvey, he solved the problem in the statistics by looking backward at the question. By looking to traditional scouting and peer review to understand the statistics, he was able to eliminate the noise. Isn’t it possible that something similar is happening in the Bronx? Because right now Curtis Granderson’s defensive statistics are dragging down his MVP campaign to the point where his ability to hold down center field for a playoff team is actually costing him ground to corner outfielders and first basemen.
For two years in a row, the Yankees have played excellent outfield defense. They have two speedy guys capable of holding down center, so one of them shifts to left. And then in right field, the least demanding position in Yankee Stadium’s outfield, they have a guy who seems about average. In 2011, the way the Yankees have positioned their outfielders combined with the distribution of fly balls hit at them, along with their own good days and bad days, spits out that the left fielder is having one of the greatest defensive seasons on record while the center fielder is having the worst season of any center fielder in the league.
I’m sure Gardner has caught a lot of balls in left center, but did those catches actually add any value to the Yankees? Or, isn’t it much more likely that Granderson could have caught most of them too? If Gardner was next in line behind Willie Mays and Andruw Jones, wouldn’t a scout have noticed in the minors? If Granderson was all of the sudden the worst center fielder in the league, wouldn’t that show up somewhere else in his speed game?
What is most likely happening is that Gardner is an excellent, though not historically great, defensive outfielder, an excellent center fielder slumming in left. And Granderson is a good center fielder who just doesn’t get to show it as much. But the Yankees don’t care because as a team, they make a lot of plays.
There are going to be more Eureka moments like James had with the first baseman. In the meantime, hopefully MVP votes and free agent contracts don’t get any loopier than usual.