The Arizona Diamondbacks played well in almost every area in 2011 - the bullpen, the starting pitching, the offense, and the defense. How valuable the team defense was depends on which defensive metric you believe. According to FanGraphs, the Diamondbacks were the best defensive team in baseball, with a Team UZR (Ultimate Zone Rating) of +55.8 Runs.  UZR also had the D'Backs as an excellent defensive team in 2010, with a total of +56.5. Using Defensive Runs Saved, based on the +/- ratings from John Dewan, the Diamondbacks were the 7th best defensive team in baseball, at +33 Runs, compared to 14th in 2010 at +22.  Based on the Total Zone defensive stats at Baseball Reference, the D'Backs finished 5th at +30 Runs, up from a 9th place ranking in 2010 at +23.  So all three systems agree that the Diamondbacks were a good defensive team in 2011; it's just a question of whether they were the best, or simply very good. Let's take a closer look at the Diamondbacks' defense in 2011.

This is an area that the Diamondbacks clearly improved in 2011. The D'Backs only allowed 61 SB for the season, the lowest total in the NL. In addition, they caught 43 out of 104 attempted basestealers for a 41% rate, 6% higher than any other team in the NL. Both Henry Blanco and Miguel Montero were excellent in this area, with Blanco nabbing 46% while Montero caught 40%. The team had allowed 115 SB in 2010, with only a 24% Caught Stealing rate. The pitching staff also deserves some credit for this, as the Diamondbacks spent a lot of time in Spring Training working on pickoffs and holding baserunners. 

The Diamondbacks also had only 39 Wild Pitches, good for 2nd in the league, and were charged with only 9 Passed Balls, ranking 7th. In 2010, the team was charged with 82 WPs and 15 PBs. Finally, Miguel Montero was also rated very highly in framing pitches. Overall, a very good defensive season for the Diamondbacks' catchers.

Middle Infielders
The defensive metrics vary significantly for many of the middle Diamondbacks' infielders. The table below shows the defensive ratings from UZR (FanGraphs) , DRS (Plus/Minus), FRAA (from Baseball Prospectus) and Total Zone (Baseball Reference). UZR and DRS are both zone-based metrics that use location and velocity data to compare plays made to those by other fielders. FRAA and TZ are based only on plays made, from play-by-play data, but without the zones or velocity effects.


Player UZR DRS FRAA TZ FanScore
Stephen Drew 4.5 -1 -2.6 0 71
Ryan Roberts 4.3 4 1.9 7 58
Aaron Hill 4.1 4 2.2 6 59
John McDonald 4.0 4 1.2 0 75
Kelly Johnson 2.6 -4 -1.4 -3 46
Josh Wilson 0.5 1 0.1 1
Cody Ransom 0.0 0 0.6 -2 48
Willie Bloomquist -3.6 -5 -3.3 -1 45

The interesting thing about the UZR data is that UZR likes all of the Diamondbacks' middle infielders, except for Willie Bloomquist. Another suspicious factor is that Hill was rated negatively while in Toronto (-3.4) but very highly with Arizona (+4.1). Similarly, Kelly Johnson was rated positively in Arizona (+2.6) but slightly negative in Toronto (-0.1). It really seems like the UZR data in Arizona is biased towards middle infielders, or perhaps the park corrections haven't been figured out correctly yet.

The only real consensus is that Hill and Roberts were pretty good in Arizona, while Bloomquist was a little below average. Looking at the evaluations by fans from Tom Tango's Fans' Survey, four Diamondbacks are rated above average - McDonald, Drew, Hill, and Roberts. McDonald in particular is rated very highly for good hands and footwork.

Corner Infielders
The defensive data for the corner infielders is also a little strange. Paul Goldschmidt scores negatively in all four metrics, but most observers felt that he was about average, and certainly better than Juan Miranda. The four stats also agree on Brandon Allen, who played well defensively over 11 games. The sample sizes are small for all of these players, but it really looks like these stats are pretty questionable for evaluating first basemen. The fans liked Goldschmidt much better, giving him an Average Rating of 55, or slightly above average. Meanwhile, Allen, Nady, Miranda, and Branyan were all rated as the worst defensive players on the team.

Among the third basemen, Mora scored well in UZR, but almost no one who watched him play this year thought he was fielding particularly well. In the Fans' Survey, Mora had an average rating of 37, near the bottom of the team. 

Player UZR DRS FRAA TZ FanScore
Melvin Mora 2.5 -1 0.7 3 37
Brandon Allen 1.4 2 0.9 3 31
Sean Burroughs 1.3 1 0.0 -3 46
Geoff Blum 0.9 1 0.3 -1
Russell Branyan 0.8 2 0.3 0 19
Xavier Nady 0.8 1 -1.7 2 31
Juan Miranda -0.4 -3 -1.2 -3 20
Paul Goldschmidt -1.3 -5 -2.4 -5 55
Lyle Overbay -1.5 -1 0.8 0

We had looked at the impressive UZR numbers of the Diamondbacks' outfielders in September, and had commented on the correlation between fly-ball rates and high UZR scores. But even if the high UZR numbers are not completely believable, there is little question that all three Diamondbacks' starting outfielders cover a lot of ground in the outfield. The end-of-the-year UZR numbers actually moved quite a bit since September, as Parra's UZR fell quite a bit over the last month of the season while Young's went up.

Player UZR DRS FRAA TZ FanScore
Chris Young 14.1 6 -5.9 18 68
Gerardo Parra 9.6 11 14.9 3 82
Justin Upton 7.7 3 4.3 -8 65
Collin Cowgill 3.9 3 1.9 -1 57
Cole Gillespie -0.1 0 0.0 1
Wily Mo Pena -0.2 -1 -0.1 0

Young's poor rating from FRAA is probably due to to the fact that the Diamondbacks were near the middle of the pack in BABIP (Batting Average on Balls In Play) despite being the most extreme fly-ball pitching staff in MLB (Fly balls are much more likely to be converted to outs, 88% compared to 75% for ground balls and 26% for line drives). But is certainly strange that FRAA rates Young so poorly while TZ has him as the best CF in the league. Both Young and Parra are finalists for NL Gold Gloves, which will be announced on Tuesday, November 1st.

Justin Upton was not a Gold Glove finalist, probably because of the 13 errors he made in RF. Despite that, Upton had excellent range and prevented many doubles and triples defensively. He played well enough that he won the Fielding Bible award for RF, which is voted on by 10 baseball experts. Young finished 2nd among all CF while Parra was 3rd among LF.

In the Fans' voting, Parra finished with an average rating of 82, highest on the team, with Young (68) and Upton (65) both rating as above average.

The Diamondbacks stood a big step forward defensively in 2011. The biggest improvement was probably behind the plate, where Montero and Blanco turned into the best duo at preventing stolen bases. The pair also did very well at blocking pitches in the dirt and with framing pitches. The second big improvement was from Gerardo Parra becoming the regular LF, as Parra showed an outstanding arm combined with very good range. Outfielders Chris Young and Justin Upton showed great range in the outfield, and all three outfielders may win defensive awards for the year. The team also got a defensive boost from mid-season additions AaRon Hill and John McDonald, and unexpectedly good defense from Ryan Roberts. 

Looking ahead to the 2012 season, all three outfielders will return, along with Montero and Roberts. One big question mark will be at Shortstop - will Stephen Drew still be an above-average defensive player after this season's ankle injury? The other question is at Second Base - will Aaron Hill be re-signed? If Hill is not brought back, then Ryan Roberts could play at either 2B or 3B, and the team would need to sign another free agent to complete the infield. Goldschmidt will be the likely starter at 1B, and he should be adequate there, even if the defensive metrics don't seem to like him.