In the bottom of the second inning during the series finale in Pittsburgh, Chris Owings clanked a routine ground-ball off the bat of Francisco Cervelli. Three batters later, Pirates' pitcher Gerrit Cole clubbed a three-run homer, which brought home the thirteenth unearned run allowed by the Diamondbacks this season. That's more than twice the number allowed through 49 games last season, when they had been charged with just six. The team is currently on pace for 102 errors, more than any season since 2010. And it's not just the relatively blunt tool of errors; the more advanced metrics also show the defense as significantly worse this year.
But to start with the obvious errors, it has been a problem all around the diamond - it's not just the obvious location of center-field, where the loss of a Gold Glove winner in A.J. Pollock would obviously be felt, not to mention his replacement with a shortstop. Even many of the returning players have been more gaffe-prone this season. Below, is a chart listing the eight Diamondbacks with 300 or more innings played in the field this year, along with their innings, error totals and F% for both 2016 and 2015. [Stats are AZ only, except for Segura]
There is only one genuine improvement: Segura. Tomas's is largely a mirage, a result of his move from the hot corner to the outfield: two-thirds of his errors in 2015 came at 3B. Purely as an outfielder, his fielding percentage has joined the rest of his team-mates in dropping, from .975 in 2015 to .964 this season. Segura's glove appears to have benefited from getting out of Milwaukee even more than his bat. Over the previous three seasons, he committed a total of 50 errors: here, he has 43 consecutive error-less games, though admittedly, most have been at second, a less-taxing defensive position [last year in the majors, 2B had a .985 F%; SS was .973%]
The drop-off overall may seem slight, from .986 to .984. But it's not limited to errors. The team's defensive efficiency (the percentage of balls in play turned into outs) is also sharply lower: Last year, the Diamondbacks ranked 4th in the National League, at 69.3%; In 2016, that figure is down to 67.3%; again, it may seem a small decline, but is enough to mean Arizona are now dead-last in their league. If sustained, it will likely be the worst mark in franchise history (we don't have that stat for 1998).
There's evidence to suggest that it is, as you might suspect, the outfield which is responsible for much of the drop-off. Last year, two plus defenders, in Pollock and Ender Inciarte, started 143 and 116 games for the Diamondbacks: it's entirely likely we won't see either of them at all in 2016. Instead, of the four players to have 10 or more starts thus far, we have three players converted from other positions (Owings, Drury and David Peralta) plus Tomas. On the surface, it hasn't been too bad: the outfield is on pace for 20 errors this season, only a handful more than last year.
But the deeper you look, the flakier that thin veneer of defensive respectability becomes. The sheer number of outs made by the outfield is down. In 2015, they averaged 6.4 per nine innings. This season, that's down to 5.5. We also see a sharp uptick on batting average on fly-balls in play from last year. This isn't the case for ground-balls where BABIP has remained almost the same (indeed, dropping slightly, from .239 to .236). But BABIP for fly-balls has jumped by over 45%, from .055 to .080. As a result batting average overall on fly-balls, including home-runs, has increased from .137 to .176. This is, obviously, not a good thing.
The advanced metrics reflect this. The 2015 D-backs had a UZR per 150 games played of 4.2. The same figure this year is -7.1, almost entirely due to an implosion on the "range" element. that passes the eye test. It's the lowest figure since the -10.7 posted in 2005, when the outfield was "patrolled" (and I use quotes advisedly), mostly by late-career Luis Gonzalez, Shawn Green and the worst outfielder per UZR in Diamondbacks history, Jose Cruz Jr. If we're not that bad this season, it's probably about what you'd expect when there have been games where all our outfield has had almost no experience there, prior to this year.
The effect is mitigated somewhat, when you take into account the acceptable infield defense, but the overall UZR/150 figure, at -7.1, remains to this point the lowest it has been since 2008. Other metrics are somewhat less pessimistic, yet they tend to agree that this defense is significantly worse than previously, In a year when our offense appears also to have taken a step back, and our pitching isn't anywhere near as good as we hoped, it doesn't appear the third side of the triangle is immune to the malaise plaguing the 2016 D-backs.