Touching BasesMarch 18, 2009
The UZR Era
By Jeremy Greenhouse
"The interesting question is why defense is so much more difficult to quantify than offense in all sports. Perhaps defense by its nature involves more interaction between individuals than individual actions, and perhaps the way to get past that is to embrace the concept and measure combinations of players." -- Bill James

Over the offseason, fangraphs unveiled Ultimate Zone Rating, a defensive metric developed by Mitchel Lichtman that measures how efficient a fielder is at turning balls in his area of responsibility into outs. The data, tracked by Baseball Info Solutions, ranges back to 2002 and is converted neatly into a runs saved figure. I’d like to give an overview of some notable teams and players throughout the years UZR has been available. As defense is a team effort, here’s a visual representation of how each team’s outfield has performed during the UZR era. The best outfield defenses, that convert balls in play into outs at a high rate and limit advancement of baserunners with their arms, will be in the top right, while the worst will be in the bottom left.

ARM rating is uncorrelated with an outfielder's range, though the measures are not independent, since the amount of time it takes a fielder to reach the ball affects how he is able to hold baserunners. The value of outfield arms, which is usually not mentioned when evaluating team defense, can add or subtract 20 runs a year, so it’s definitely significant. However, to find an outfield’s true talent when it comes to arms, any figures would probably have to be heavily regressed.

The 2004-2007 Braves consistently had the best outfield in the Majors. With Andruw Jones patrolling center, the Braves were set at the second most influential defensive position on the diamond when it comes to fielding.* Jones was flanked in left by the likes of Ryan Langerhans, Matt Diaz, and Willie Harris, who all had great range. And in right, the Braves trotted out stalwart Jeff Francoeur and his rocket arm. Meanwhile, the Yankees from 2002-2006 consistently fielded the worst outfield in the Majors.

*The traditional defensive spectrum is well-known, but for reference—shortstops and center fielders are expected to make just over 2.5 outs per nine by UZR, followed by second basemen. Right fielders and third baseman come in at two expected outs per nine and left fielders a bit less. The fact that right fielders are expected to make more outs than left fielders goes against traditional baseball knowledge, which I believe states that fielders with more range should play left. Batters tend to hit more fly balls to the opposite field than to the pull field, and righties bat more than lefties, so this makes sense. Perhaps if there's a defensive whiz in right, say Ichiro Suzuki or Jayson Werth, they should switch fields if at the same time there's an albatross in left, say Raul Ibanez, depending on batter handedness and spray-chart information. Finally, first basemen come in at about one expected out per nine, though that of course does not account for throws first basemen handle.*

The Nationals/Expos franchise has put up the best ARM rating in the UZR era. In each of the final three years of their existence, the Expos' outfield led the league in ARM thanks to Vladimir Guerrero, Juan Rivera, Endy Chavez, and Brad Wilkerson. Of course, only Chavez had any range, so their defense as a whole trended around average. The collective outfield arms of the 2003 Detroit Tigers, the worst team ever (?), cost the team 20 runs, one of the worst marks on record. However, that number doesn’t really stand out among that team’s .300 on-base percentage, and 1.37 strikeout-to-walk ratio. What's the opposite of nitpicking?

The Rays' worst-to-first success has been fairly well documented. Their biggest improvement may have been their outfield defense, which saved nearly 70 runs more in 2008 than it did in 2007—the largest improvement by any outfield in the UZR era. B.J. Upton and Carl Crawford's numbers skyrocketed while Eric Hinske and Gabe Gross were great replacements for Delmon Young. and Jonny Gomes. Considering left and right fielders have remained constant for the Rays both years, I wonder to what extent the difference can be attributed to individual improvements from Upton and Crawford, and how much of the success was thanks to the unit meshing together in terms of positioning. The Rays went on to the World Series, where they met the Phillies, who incidentally posted the exact same 74.3 team UZR. The Phillies were aided by their ARM rating of 22.1, the highest single-season mark to date. Pat Burrell was the only bad defender on the team, but his arm almost made made up for what he lacked in range, while Shane Victorino and Jayson Werth are stellar all-around players.

Now let's take a look at the infield.

Though the Rays improved their infield by 50 runs in UZR from 2007-2008, the second biggest year-to-year leap by an infield, they trailed well behind the 2006 Kansas City Royals. In 2005, the Royals infield was 47 runs below average. In 2006, they were 32 runs above average. Nevertheless, the pitching staff still allowed more runs in '06 than in '05! In 2006, KC’s 5.29 FIP was the highest single season mark of any club ridiculous run environments seen in 2000. But their defense did make a marked improvement. The Royals saved over 110 total runs on defense in 2006 compared to 2005, thanks to the additions of Mark Grudzielanek, Doug Mientkiewicz, and Reggie Sanders. The following year, 2007, the Royals 78.5 UZR in was the highest single-season total for any team since 2002. Mark Teahen was terrible in 2005, but he found his footing on both ends of the field in 2006, posting an average UZR and an .874 OPS. Then in 2007, he put together another solid year, losing production with the bat but gaining ground with the glove in his move to right field. Unfortunately, it all fell apart for him last year, and now we’ll see how he does at second base. Also in 2007, Tony Pena actually merited playing time, finishing second in UZR for shortstops behind only Omar Vizquel.

Remember that All-Star studded Rangers infield of Hank Blalock, Michael Young, Alfonso Soriano, and Mark Teixeira? It turns out they gave away a whole lot of their value on defense. In 2005, the Rangers infield had a UZR of -62.4, the worst ever. The 2007 Giants had the best infield on record. In the same vein, the Athletics infield last year had the highest double play run total though it's a matter of only a dozen or so runs. Lastly, The Phillies have had the best infield defense in the last seven years, while the Rangers and Yankees have been worst.

The 2008 Phillies infield defense has been the topic of some discussion. Ryan Howard was so bad that the entire defense shifted to cover him, maximizing the range of Chase Utley, Jimmy Rollins, and Pedro Feliz.. The Phils' infield saved 40 runs last year, an excellent figure, no matter how you slice it. To actually isolate Utley from Howard, it would probably be best to use a "With or Without You" analysis, comparing Utley's performance with Howard on the field against his performance with other first basemen, though the sample would be impossibly small.

I am forever on a quest to find why teams or players are "clutch," and out-perfrom their expectations in high-leverage situations. I constantly correlate variables with fangraphs' clutch score, and I have so far found very weak correlations with strikeout rate and baserunning on offense, meaning teams that run the bases well and rarely strike out for some reason do better in more important situations. Now, with fielding, I found a weak correlation between clutch and double play runs. I suspect some teams are adept at employing relievers who specialize in inducing groundballs at opportune times, and therefore leverage their double play runs. It's also possible that some teams are able to effectively manage the intentional walk to their advantage late in games, setting up the double play.

I think splitting up defenses into infield and outfield units is a comprehensive method for evaluating team defenses, but it's often more interesting to look at individual players, so I'll leave you with the time leaders and laggards in UZR for all seasons from 2002-2008.


Andruw Jones has by far the highest career UZR. By Sean Smith’s Wins Above Replacement leaderboard, Jones is 77th in WAR, making him a borderline Hall of Fame candidate. Any sort of resurgence would make him a near lock, but it’s currently looking bleak as is.

Arms are an area of study that have belonged to John Walsh, but UZR's ARM metric shows similar results, and confirms many players' reputations. Alex Rios has paced the league in ARM runs, while Ichiro and Francoeur trail slightly. In 2007, Francoeur's arm was the most valuable of any outfielder during the UZR era. On the other end, Juan Pierre's arm has been laughably bad, coming in nearly 20 runs worse than anyone else's over the years.

Jack Wilson was slickest at turning the double play in the UZR era, and he certainly does make it look pretty, if I do say so myself.

Finally, the Yankees. Bernie Williams and Hideki Matsui show up on the bottom ten list, and Derek Jeter, Gary Sheffield, Bobby Abreu, Jason Giambi and Johnny Damon also show up in the bottom 10th percentile, so yeah, the Yankees haven't valued defense highly.


Seeing Bernie bringing up the rear is painful, but rings true. He was a poor defender before the knee injury (early '03), and then he just plain fell off a cliff. The Ghost of Bernie kept playing CF, though, and the organization managed to look at Carlos Beltran and say "no thanks." For that (not that alone, of course), they've paid.

The 2005 Yankees rated out as the worst defense of all time, didn't they? Thankfully, they seem to have (belatedly) gotten the message.

The 2005 Yankees seem like an outlier. Their UZR was about twice as bad as any other team. The Yankees' decisions to pass on Beltran and Vlad and sign Damon and Sheffield are regrettable indeed.

Frankly, I think it'd be silly if Andruw Jones couldn't catch on somewhere as a defensive replacement or just a glove-first CF for some 2nd division team. While the bat is most likely gone, you can't convince me that guys like Corey Patterson and Willy Taveras are better options, all things considered.

Well Taveras and Patterson are decent fielders too, but point taken. If Jones were to get back into shape, there's no doubt his glove could play.