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Grading the Arizona Diamondbacks

Safe to say they’ve made the honor roll so far...

With an off-day today, it’s a good point at which to take stock of the Arizona Diamondbacks and their performance so far. 11-4 is certainly a good start to the season, though as we’re not even 10% of the way through the schedule, there’s a lot of work left to be done. But let’s break down that performance a bit further, and see what we can learn about how Arizona has got to this point.


  • Runs/game = 5.01 (4th in NL)
  • BA: .254 (7th)
  • OBP: .329 (7th)
  • SLG: .445 (2nd)
  • OPS: .774 (4th)
  • OPS+: 93 (9th)
  • wRC+: 100 (7th)

The raw numbers rate the team better than the park-adjusted figures, but it’s worth remembering that any impact of the humidor has likely not yet been included in park factors, which will still see Chase Field as very hitter-friendly. That probably isn’t the case, though we’re still a long way from being able to judge its impact. But for what it’s worth, here are the figures from the first six games at Chase Field this year and last:
2017: 45 runs, 7 HR, .322/.383/.523 = .906 OPS
2018: 35 runs, 5 HR, .257/.354/.424 = .778 OPS

Obviously, different opponents, different players, so the above needs to be taken with a large dose of salt. But on the other hand, it’s also 64 points of OPS lower than the overall figure we put up at Chase in 2017. And there has been a reduction for our pitchers as well, conceding seven fewer runs (20 vs. 27) at home, with the team ERA dropping from 4.17 to 2.85. We’ll see what happens this home-stand. Grade: C+


  • Record: 7-2 (2nd)
  • ERA: 3.95 (8th)
  • FIP: 3.63 (6th)
  • xFIP: 2.96 (3rd)
  • K:BB: 3.50 (4th)
  • fWAR: 1.2 (2nd)

Our starting pitchers have been racking up the strikeouts, with a league-best K-rate of 10.8 per nine innings, which surpasses even the much-touted Mets rotation (10.5). However, they have also been walking a fair numbers, though things are likely skewed by Zack Godley’s free passathon yesterday. The home-run has been an issue too, with a dozen in 82 innings - that’s why xFIP, which regresses that rate to normal. like the D-backs best of all. Given the ERA, the 7-2 record feels a bit lucky; worth noting that two of those W’s were secured by 9-8 and 8-7 margins. But that strikeout rate is encouraging: opponents can’t get hits if they’re not putting the ball in play. Grade: B


  • Record: 4-2 (4th)
  • ERA: 1.92 (3rd)
  • FIP: 2.72 (2nd)
  • xFIP: 3.65 (7th)
  • K:BB: 2.57 (8th)
  • fWAR: 1.0 (2nd)

We see almost the reverse of the situation with our starters when we go to the bullpen. The peripherals suggest there will be some regression, particularly with regard to home-run rate. So far, our relievers have thrown 56.1 innings and allowed only two balls to leave the park. While our ground-ball rate has been better than league average (49.3% vs. 43.7%), it’s not that much better. Some of those fly-balls will leave the park eventually, so a sub-two ERA is probably not going to be sustainable in the long term. Let’s just hope when they do go over the fence, they’re not in close games and with runners on base. The walk-rate will improve when Jorge De La Rosa (6 BB in 5.1 IP) stops costing us games. Grade: B+


  • Errors: 4 (1st)
  • DefEff: .712 (2nd)
  • Arm: -0.7 (13th)
  • DPR: 0.8 (2nd)
  • RngR: 5.2 (1st)
  • ErrR: 2.8 (2nd)
  • UZR: 8.1 (1st)

Arizona’s play in the field has been very, very solid so far, especially compared to last year. In 2017, they ended the season with a UZR of -21.7, ahead only of the Padres, so for them to be already sitting at +8.1 is a huge turn-around. They’re flat out converting more balls into outs: that’s what DefEff measures, with 71.2% of balls in play becoming outs. Again, it’s a sharp improvement on 2017, where the figure was 68.7%. Going by the breakdown of UZR, it’s mostly been the team’s range which is responsible, and that makes some sense. We’re still in the very early going, but catcher’s defense as measured by Baseball Prospectus’s FRAA metric, is holding steady: third in the NL, compared to fourth last season. Grade: A


  • SB: 8 (8th)
  • SB%: 80% (4th)
  • OOB: 6 (=11th)
  • XBT%: 55% (1st)
  • BsR: 0.6 (5th)

The team has been relatively static in terms of stealing bases compared to last year - through the first fifteen games in 2017, the team had swiped 14 bags, and made almost twice as many attempts (19 vs. 10). But they have been very aggressive in terms of taking extra bases, e.g going first to third on a single. That 55% figure is up a full 10% on last season, and perhaps ties into the relatively high number of outs on the basepaths. Interestingly, all but one of the OOBs have been at second-base. And those don’t include pickoffs or caught stealing, so are presumably mostly players trying to stretch singles into doubles. But we’re 8-0 thus far, for scoring from second on a single! Grade: B

We’ll revisit these in another 15-20 games or so (whenever there’s a convenient off-day) and see how things have changed.