It’s better since Hazen arrived.
Inspiration.
My inspiration was this FanGraphs article which looked at ‘Are we now in an era of Peak Centerfield Defense?’ The point that most convinced me that we are in that era was that wOBA of air balls hit to center field (excluded homers) fell more than 16% between 2008 and 2025.
Are the Diamondbacks at peak centerfield defense? Let’s look.
Diamondbacks Trends.
For the Diamondbacks, looking at air balls hit to centerfield, their wOBA improved about 8%. My view is that the improvement happened after Mike Hazen became GM. For details, see the following graph. The two gold lines show the wOBA before and after Mike Hazen became GM.
Thru 11 July. Diamondbacks. Excluded home runs. Data from Baseball Savant.
For 2015 to 2025, looking at all balls in play hit to centerfield, the Diamondbacks’ Defensive Runs Saved (DRS) slipped toward league average, while their Outs Above Average (OAA) improved to significantly better than league average. For details see following two graphs. The two gold lines show the trends.
Thru 11 July. Diamondbacks. Data from The Fielding Bible.
Thru 11 July. Diamondbacks. Data from FanGraphs.
Likely, this shows the Diamondbacks have a focus on fielding airballs. To see a broader perspective, let’s look into how DRS and OAA differ.
DRS and OAA as measures of defense have weaknesses.
These are complex measures and may evolve over time. An oversimplified view follows:
DRS considers outfielders range, arm strength, and errors. It can be influenced by shifts (assumes unshifted position), and by park factors. Its’ unit of measure is runs.
OAA considers distance traveled and time to get to the ball and weights each play by difficulty. Shifts can make some plays easier and some plays harder. Whether shifts impact defensive wOBA is a different question. Also, OAA does not account for the impacts of arm strength and accuracy. Its’ unit of measure is outs.
Sometimes, a centerfielder’s DRS and OAA may seem to be contradictory. For example, in 2024 three centerfielders (Corbin Carroll, Jake McCarthy, and Alek Thomas) had positive OAAs and negative DRSs. For details, wee the following table.
Thru 11 July. Data from The Fielding Bible and Baseball Savant.
Is centerfield defense in 2025 near a peak?
The three graphs show that the Diamondbacks’ centerfield defense peaked in 2022. That season, Daulton Varsho and Alek Thomas were great defenders in centerfield.
On a positive note, although this season feels less likely to see the Diamondbacks in the playoffs, centerfield defensive (especially DRS and wOBA on air balls) is better than last season, and roughly as good as 2023 (when they reached the playoffs).
Is Centerfield defense better in the first four innings?
Comparing the first four innings to the second four innings showed that centerfield defense on air balls was better in the early innings (wOBA .345 vs .385). Possibly the starting pitchers pitched in a way that characteristics of batted balls made it easier to field them. And the Diamondbacks’ problems with the bullpen are very well known.
Which pitchers have better centerfield defense?
Nine pitchers had at least 10 air balls batted to centerfield. The best were Shelby Miller, Jalen Beeks, and Zac Gallen. Because these are known to be remarkable pitchers, there is support for the idea that pitchers influence the characteristics of batted balls. Details are in the following table.
Thru 11 July. Diamondbacks. Data from Baseball Savant.
Summary.
For the Diamondbacks, looking at air balls hit to centerfield, their wOBA improved about 8%. My view is that the improvement happened after Mike Hazen became GM.
For 2015 to 2025, looking at all balls in play hit to centerfield, the Diamondbacks’ Defensive Runs Saved (DRS) slipped toward league average, while their Outs Above Average (OAA) improved to significantly better than league average.
Centerfield defense is a team effort, with impact from how outfielders are shifted and the quality of balls hit to the outfield. Likely, some pitchers positively influence that characteristics of batted balls.
In 2022, the Diamondbacks centerfield defense peaked. This season, centerfield defense is better than last season and roughly as good as 2023.
Centerfield defense on air balls was better in the first four innings, possibly because characteristics of batted balls made them more fieldable.