When Mariano Rivera and the Yankees sealed the deal on their 5-2 victory over the Indians last night, it marked the 18th game in a row in which the Yankees had not committed an error. Over that span of games, the Yankees have gone 14-4, and the team seems to be living proof of the adage “defense wins games.”

But on its face, this errorless streak is a bit deceptive it doesn’t really tell us very much about how the Yankees have been doing in the field. It does tell us that the Yankees have been sure-handed and that the team’s pitchers can trust the other eight men on the field. It does tell us that the Yankees are fielding the balls they can get to cleanly, but it does not tell us if the Yankees are getting to more balls and thus are turning more potential hits into outs.

For that, we have to move beyond the limited statistic of errors and look at some of the new defensive metrics that assess range and defensive efficiency. Over the weekend, long-time RAB reader Jamal G. commented on the defense: “I think the huge defensive statistic that people should be paying attention to is the Yankees’ being 5th in the AL (12th in MLB) in Team Defensive Efficiency with a .697%. I expected the defense to be better, but in the 18-20 range; this is surprisingly awesome.”

I had recruited Jamal to write a longer guest column for us, but then the new Statistician Magician beat us to the punch. In his piece, he analyzes the various parts that make up the Yankee defensive whole and concludes that, while so far there are no stand-outs, the team is much improved over recent years. He concludes:

The team’s overall defense is close to average. But that is much improved based on what we all saw last season. And because of this, they don’t have a real flaw: above-average pitching, once it comes around completely; a very good offense when healthy; and now a decent enough defense too.

If they keep up the glove-work, which they should, it will be a great step in the right direction for Cashman and the rest of the organization. Because Cashman seeing their success coincide with an improvement on defense, will let him truly understand what he has been missing for some time now.

…Because defense matters.

With Derek Jeter’s new-found range, Robinson Cano’s resurgence and some excellent outfield defense after a few years of Matsui-Damon-Abreu, the Yankees are turning balls that once were hit into outs. Their starting pitchers can go deeper into games, and the team enjoys fewer opposing base runners.

Right now, it’s all clicking for the Yanks, and their defense is a large part of it. The error-less streak looks good on paper and makes for some nice headlines, but it tells only part of the story. As much as they are winning with hitting and winning with pitching, the Yankees are starting to win with fielding too, and as Flying Joba Chamberlain showed last night, it looks good.

Photo by Mark Duncan for the Associated Press.

Defensive quantification, the final frontier. Since its introduction to mainstream culture, baseball has been a sport obsessed with statistics. Yet one aspect of the game which has flustered analysts for years is defense. We’ve seen some breakthroughs over the past few years, with Zone Rating, Ultimate Zone Rating, John Dewan’s plus minus, and Dave Pinto’s PMR, but none of them provide us with the concrete information we get from batting and pitching stats. All that means is that we should be looking for other ways to accurately evaluate defensive and its effect on the outcome of games.

On Wednesday, Rob Neyer explored the first-place Texas Rangers and their improved pitching staff. A team which has ranked no better than 12 out of 14 AL teams the past four years is currently sixth best in the young season. They’ve combined that fortune, which comes mostly on the effort of Kevin Millwood and his 2.92 ERA, with 191 runs scored, two behind Boston for second most in the AL. While it might sound funny to hear “first place Texas Rangers,” it’s not so odd to hear that the team with the sixth-best pitching and third-best offense leads its division.

At FanGraphs today, Dave Cameron flips the argument a bit and gives the Rangers defense a lot of credit for the team’s pitching success. His evidence: the team’s FIP — that is, Fielding Independent Pitching, defined below — is actually worse this year, at 5.17, than it was all of last year, 4.83. This would indicate that the defense is doing quite the job in converting balls in play into outs.

We can see this from an anecdotal and a statistical standpoint. The Rangers rearranged their infield over the winter in order to eradicate a few of their weaknesses. For instance, the team featured a revolving door at third base, none of whom were any good at the position, as evidenced by their -26.7 collective UZR. At shortstop, Michael Young featured a -5.4 UZR. So the Rangers slid Young over to third, and though it hasn’t gone quite as planned there’s still time for him to make the adjustment. They replaced him with defensive whiz Elvis Andrus, who is into the positive UZR rankings already. They moved Chris Davis over to first, where his bat will play just fine and he’s less of a liability than he was at third. Even Ian Kinsler is playing better this year, projecting to a 14.4 UZR/150 after negative values in his earlier years.

The question, of course, is how much of this is related to a small sample size and how much is for real. We can’t tell yet if Kinsler is getting extremely lucky or if having Andrus up the middle is giving him a boost. We don’t know if Michael Young is bad at third — and that comes in two senses. First, is he really bad, in the sense of, is UZR accurately depicting his ability? Second, is he just bad, or is this just a transition after having played shortstop from 2004 through 2008? Perhaps the biggest question here is, how does this relate to the Yankees?

One area in which the Yanks could have really done something to improve this off-season was on defense. Signing Mark Teixeira improved the glovework at first, but what about the rest of the infield? In order to see an improvement, they’d have to see Robinson Cano return to 2007 form, Jeter maintain what he did in 2008, and for A-Rod to continue being league average. Is it working? Well, the team has a 5.18 team FIP against a 5.64 team ERA, so it doesn’t look like it. That’s not the final word, of course — comparing FIP to ERA is just a tool to aid in analysis. But, with this one readily-available tool, it doesn’t appear the Yanks defense is doing much to bail out the pitchers.

It’s tough to make any kind of far-reaching judgments when the season is barely a month over. However, in the early going it looks like the Yanks are having problems all around: with their pitching, with their defense, and with their hitting, particularly with runners in scoring position. That’s quite a stack of problems for a team to overcome. The saving grace is that the Yankees have the talent to do it. They’re currently 10th in the AL in UZR, though they’re off of 9th place by a decent margin. Still, with even a modest improvement from here on out — say, league average — they can make the necessary adjustments and play this season like we’d imagined it in March.

Yesterday, Dave Pinto looked at the PMR for defense behind pitchers. For those unfamiliar with PMR, it stands for Probabilistic Model of Range, and it compares the number of balls in play and compares it to predicted outs and actual outs. Read the link above for a better explanation and past PMR ratings. The defense behind pitchers is a neat one, because we’re supposed to see how a defense benefitted or hurt a pitcher.

The Yankees kind of stick out on this list. First is Chien-Ming Wang, who seems to be the pitcher most helped by his defense. On the other end of the spectrum are Andy Pettitte and Darrell Rasner, who are among the most hurt by the defense behind them. So what gives? Can the Yankees defense be like eight Omar Vizquels when Wang pitches, but turn into eight Jason Giambis when Pettitte and Rasner take the hill?

Clearly, I think this has something to do with the pitcher himself. One thing I’ve noticed over the years with Wang is not only his ability to induce groundballs, but also his ability to induce poor contact. Even balls in the air don’t have much under them. Yeah, you might make Johnny move a few steps, but it’s not like he’s giving up many screamers into the gap. That’s the beauty of Chien-Ming Wang.

On the other end, with Pettitte, I’m not sure what to think. It’s comforting, I suppose, to think that the defense behind Andy, which we know isn’t among the best in the league, played a role in his poor second half. But what if he was just giving up a lot of hard-hit balls, ones that the defense had no shot at? That’s going to show in these defensive numbers, even though it’s not necessarily the defense’s fault.

Another interesting note: Dice-K was second on the list. So he gave up the fourth most walks in baseball — most in the American League — and had his defense convert the second most balls in play into outs? I’m really interested to see how next year turns out.