Towards the second half for the D-backs

The Diamondbacks go into the second half with a record of 52-39 - they have already matched their win tally for the entire season before last. They sit in an effective tie with the Dodgers at the top of the National League West, and the team appear to have the best chance of seeing post-season baseball since the end of 2017. But with 71 games left to play, there’s still work to be done. So, as we get ready to get back to it, let’s take a look at how the team got here, and what they can do to improve their chances of winning the division for the first time in a dozen years.

First half

Hitting

The Diamondbacks have set a new franchise record for hitting this year, with a collective OPS+ of 106. it’s five points better than the previous high of 101, recorded all the way back in 1999, the only other time the team has even reached 100, It’s also an eleven-point improvement over the 95 OPS+ for the team last year. Raw batting average is up 22 points and slugging by 43 points. The team has also been very active on the base-paths, stealing better than a base per game. On that basis, the franchise record for SB of 137 should be beaten with a month or so left in the season. The D-backs’ strikeouts are down: the current page of 1,246 would be the lowest for a full schedule since 2014.

Fielding

You pay your metric and take your choice. Arizona’s fielding percentage of .990 is best in the majors, stemming from an MLB low 31 errors. Total Zone’s Fielding Runs Above Average also ranks them very well, their +27 being third overall, and most in the NL. BIS’s Defensive Runs Saved is less impressed. While the Diamondbacks are still comfortably positive at +15, that’s outside the top ten in MLB. Over at Fangraphs, UZR has Arizona fifth in the majors at +12.7, and a Def of +17.4 is good enough for second, behind only the Rangers. The overall consensus appears to be that the D-backs defense is good. Precisely how good is where the discussion will begin.

Pitching

Arizona has improved her as well, though not by as much as at the plate. The ERA+ has gone up from 95 to 99, which is the best number since 2019. However, this overall figure conceals a deviation of fortunes in our rotation and bullpen. Last year, our starters had a rare season where their ERA was better than the relievers (4.05 vs. 4.58). But the figures have almost exactly flip-flopped this year, with the rotation getting worse (4.61), while the bullpen has improved (4.00). All told, the team’s ERA is up one-tenth at 4.36. The improvement in ERA+ for the D-backs is because across all of baseball, ERA is up around a third of a run on 2022, going from 3.96 to 4.28, so the team are much closer to average.

Second half

A good way to find areas for improvement is to look at the chart below. This shows the various positions, and highlights where the team ranks in Wins Above Average (WAA - note, this is different from Wins Above Replacement) compared to the rest of the teams in the National League. [It might be a little small if you’re on a mobile device, so turn your phone sideways and look at the full graphic!]

There are three areas where the team is below par (discounting PH, where no players has even a dozen PAs yet), plus a couple more that are right at league average. Let’s look at those, going from best i.e. least in need of improvement to worst.

#5. Right field: 0.0 WAA

This is perhaps a bit of a surprise, but is mostly because the D-backs rank only 10th in the NL by OPS from the position at .741. Starts so far have been mostly Jake McCarthy (41), with Corbin Carroll (21), Pavin Smith (20) and Dominic Fletcher (9) making up the remainder. It’s McCarthy (.629 OPS) and Smith (.536) who are responsible. The latter appears to have taken care of itself, but Fletcher will likely regress as his .377 BABIP does. The main source of improvement here might be if Lourdes Gurriell Jr. can pick his offense back up, and merit more playing time in left. That’d then free Carroll up for more starts here, and that’s where UZR reckons his defense has been best as well.

#4. Relief pitching: 0.0 WAA

Conversely, you might be surprised this isn’t higher, considering the D-backs have already lost five games they led in the ninth [the much worse 2022 bullpen only had six of those all year] The reality is, in general, the D-backs bullpen has been okay. Indeed, they have only 37 meltdowns (relief WP worse than -6%); no team has fewer. But when AZ melts, it’s like ice-cream in a Phoenix summer. The D-backs have eight relief appearances this year with a WP worse than -59%. That’s MOST in the majors. Adding another reliable arm is definitely something the team should look at. But bullpen help is often an overpay, since you are typically only looking at 20-30 innings from your typical impending free-agent reliever.

#3. Designated hitter: -0.5 WAA

This is an NL-wide problem, with only three teams above average at the positions; I think they are still coming to terms with what is a relatively new roster spot. Gurriell and Smith have the bulk of the playing time here with 114 and 100 PAs respectively. The former has struggled, with a .666 OPS compared to .888 when he plays the field. Other internal options are limited, with Evan Longoria needed elsewhere and Kyle Lewis as bad at the plate as he was in Seattle. This may be the most likely route. I’d love to see something like the J.D. Martinez trade in 2017, who then blasted Arizona into the NLDS with the best second-half in franchise history. Can Mike Hazen strike gold again?

#2. Third base: -0.7 WAA

Ah, remember the halcyon days of preseason, when we were arguing over who was the future at the hot corner, Emmanuel Rivera or Josh Rojas? Turns out the answer was C) Evan Longoria. Between them, Rivera and Rojas have combined for one home-run in 382 plate-appearances this season. Josh has been sent to Reno, and over his last 125 PA Emmanuel has a .596 OPS and a K:BB of 29:6. Longo has been everything we wanted from when he was signed, mashing left-handers at a .909 clip. But if we can get a long-term solution here, this is where I can see Hazen spending prospect capital, to get someone who can help the team both in the second half, and in subsequent seasons.

#1. Starting pitching: -1.0 WAA

Never mind “Spahn and Sain and pray for rain”, it’s “Zac and Merrill, then we’re in peril.” Not sure even the 2001-02 D-backs had such a drop-off from the 1-2 punch to the rest of the rotation:
Gallen and Kelly: 20-7, 213.1 IP, 172 H, 85 R, 74 ER, 19 HR, 60 BB, 223 SO, 3.12 ERA
The rest: 11-18. 272.2 IP, 303 H, 180 R, 175 ER, 45 HR, 114 BB, 203 SO. 5.78 ERA
Hopefully Tommy Henry has figured it out: his last four starts have covered 24.2 IP with an ERA of 1.48. But the FIP in that time is 4.51, so I’m not optimistic. Merrill Kelly returning fit after the break will be a big help, but if anything leads to the team falling apart down the stretch, I suspect it’ll be this rotation of shadows and mirrors at the back end.

I would expect the above to be the areas on which Mike Hazen is focused as we head towards the trade deadline. The philosophy has been clear over the past few seasons, that the team looks for moves which will typically offer sustained improvement, rather than just a short-term boost, and I would expect that to continue. However, the expanded playoffs mean there are more teams than ever with a shot, and so demand for players is likely to exceed supply. We’ve seen Hazen pull off unexpected trades before, and I suspect this deadline period will be little different. But it’s nice to be a buyer for once: seems like forever since the D-backs have been on that side of the counter!