The Declining Diamondbacks Defense

Overview

In 2013, almost all the metrics agree, the Diamondbacks had one of the best defenses in baseball. Fangraphs DEF statistic had the team at almost 50 runs saved over MLB average, the best in the National League and second only to the Royals. The Fielding Bible's Defensive Runs Saved (DRS) agrees with the ranking, but puts the total value of Arizona'd fielding even higher, at 86 runs. Gold Gloves wee awarded to Paul Goldschmidt and Gerardo Parra - both well deserved, but the vast majority of the team played well in this area.

Fast forward a year, and much has changed. Our DEF has already plummeted all the way to -10.2, ahead of only the Nationals in the NL, and DRS concurs, currently valuing the Diamondbacks defense as costing them 12 runs compared to average, with an overall rank of 23rd. If that continues at the same pace for the rest of the season, the overall turnaround from last season, as measured  by DRS, will be getting close to a hundred runs, with the team posting their worst defensive mark since 2008.

Now, we should remember that defensive numbers are volatile: for individuals, even a full season can contain a lot of random variance. But these figures do seem to match the eye test. As fans, you won't have needed to watch many Diamondbacks games to see them kicking the ball around and airmailing throws. The team knows it. At the end of April, Kirk Gibson said, "It's not coming naturally for us. We're putting more pressure on ourselves. We've had more pressure on us, other teams pushing and putting a lot of balls in play. We've had a lot of base runners on and guys are trying to make plays. It's uncharacteristic, but it is characteristic of a team that's struggling."

Errors

Last year, the Diamondbacks were charged with only 75 errors. Through the first 37 games, they are on pace for 136, a number reached only once in franchise history (2004, when they made 139). And that number may actually be low. Remember ThatPlay.gif by Mark Trumbo from the very first game? Not scored an error. Or, more recently, Alfredo Marte's throw home in the Brewers' five-run first on Tuesday? Not an error: it was scored as "runner advancing on throw", rather than, arguably more accurately, as "runner advanced after outfielder suddenly believed he was attempting to launch a satellite into low Earth orbit."

Something that stands out, possibly lending support to Gibson's theory about self-imposed pressure, is that 19 of the errors, 61%, were throwing mistakes. That's unusual, as typically, the majority of plays scored as E's are fielding ones - 47% across all baseball. Only the Orioles (62.5%) have a higher percentage than us, and they've made  about half as many errors in total (16, ten of them on throws). The 19 throwing errors committed by the Diamondbacks are three more than any other team in the majors to date, so it does seem this has been a particularly significant problem for the team.

Leading the charge is Martin Prado. He made ten errors all last year, but is already at seven, even though we won't reach the quarter mark until next week. Put another way, his error percentage in 2013 was 2.9%; this time, it's more than 2 1/2 times that, at 7.1%. But it hasn't been throwing which has been the issue for Prado, with only two of the seven gaffes being in that department. Also racking them up are Miguel Montero, who has matched his 2013 tally with five errors; and Chris Owings who, despite the talk of "COD", has a much lower fielding percentage thanks to his five errors, than Didi Gregorius last year, at .953 vs. 971.

Defending the running game

This has been an area of particular pain for the Diamondbacks, with 25 of the 28 base-stealing attempts being successful. The resulting 89% rate trails only the Cubs (27 of 30) in the league. It's a sharp drop from last year, when the same number was only 69%, better than league average (72% in 2013; 74% this year). Neither Montero nor Tuffy Gosewisch have been good. Miggy is 18-for-21, less than half his rate last year, and Gosewisch has yet to nail anyone, in seven attempts. Obviously, there's more to catching than this, but Gosewisch was supposed to be defense first. His OPS+ of 17 doesn't suggest much offensive value.

It's harder to say how the team is in other areas: while there are baserunning numbers which show how good a team is at taking an extra base, that only seems to be available for them at the plate, not when they are on the mound. I do note the 2014 Diamondbacks lead the league in bases advanced against, which covers things like wild pitches, passed balls, fly balls, balks and defensive indifference. We have also yet to pick off a single base-runner, which we did ten times in 2013.

Position by position

The chart below breaks down the DEF by position - before you ask, it doesn't cover pitchers - and extrapolates what the figure would be at the end of the season, based on the current rate (yes, we'll take all the dangers of that as read!). It also includes the actual figure for 2013, and a plus/minus figure.

That seems quite surprising, doesn't it? If I'd been asked to come up with the positions where the team had struggled defensively this year, I might have gone for third, with Prado and his errors, or left, where the deer and the Trumbo roam. But it appears (and I'll repeat the taking of the warnings as read) that, so far, it has been second and right that have been the real problems so far. With regard to the latter, it appears Parra is a shadow of his 2013 self: the Fangraphs breakdown has him below average for range, arm and errors to date, when he was among the league leaders, particularly in the first two categories.

At second base, the situation is slightly different. Last year, the numbers show our best defenders there were Chris Owings, Josh Wilson and Cliff Pennington, who combined to be +4.2 runs. Aaron Hill and Prado together were -1.4, with Willie Bloomquist also negative. None of last year's positive contributors have played even a single inning there this campaign. Instead, Prado has been awful, worth -1.4 runs in only 26 innings, and Hill is also below his rate from last season. However, Hill's 113 OPS+ seems like reason to cut him some slack, even if his defense does turn out to be on the downside of the aging curve (he is now 32, after all).

The future

A team can typically get away with sloppy defense if they have an overpowering pitching staff who get a lot of strikeouts; that helps, because fewer balls in play means fewer chance for errors. That's Washington, the only team currently K'ing more than a batter per inning, so their -10.9 team DEF has less impact. It certainly isn't us, especially our rotation. The average NL starter this year fans 7.6/9IP, and only Bolsinger (23.2 IP, 22 K) reaches that rate for his major-league career. Even with McCarthy's improved K-rate, our overall number is 6.9, 13th in the league. This is a staff which will see lots of contact, and needs defense behind it that can handle the results.

I tend to think some of this is just small sample size, in particular, Parra's drop-off in right-field, which doesn't seem to match the eye test - admittedly, I haven't exactly watched every inning of every game [I doubt many people outside the team dugout have!]. I certainly hope that's the case. But on the other hand, a team which is shaky on both hitting and pitching absolutely cannot afford to go handing the opposition extra outs and free bases. It'll be interesting to revisit these numbers around the All-Star break, and see if things have settled down.