The Diamondbacks Have Wilted in the Heat of a Playoff Race

In an attempt to arrest a slide that began in early July, the Diamondbacks were busy in the run-up to the August 1 trade deadline, but so far, their moves haven’t been enough to turn things around. In fact, they have yet to win a game in August, having finished a seven-game road trip by losing six in a row to the Giants and Twins. On Sunday, their highest-profile deadline addition, former Mariners closer Paul Sewald, failed to retire a batter in his first save opportunity since the trade. Instead, he served up a game-tying homer to Max Kepler on his first pitch and then, after a walk, a two-run walk-off homer to Matt Wallner. Ouch.

After spending the majority of the first half leading the NL West, the Diamondbacks have slipped to sixth in the NL Wild Card race, 1.5 games behind the Cubs and Reds, who are tied for the third spot. Their trend is actually worse than that. Since winning on July 1 to lift their record to 50-34 and restore their NL West lead to three games, the Snakes have gone 7-22 (.241). That’s worse than the A’s (9-19, .321) or any other team in the majors. It’s not as though they’ve been particularly jobbed in the process; their Pythagenpat record is the majors’ worst in that span as well:

To be fair, the Diamondbacks weren’t expected to be a powerhouse this year; after going 74-88 last year, they projected for 78.4 wins via our preseason Playoff Odds. In a slow-starting NL West, they took over a share of first place for the first time on April 8, when they were 5-4, and finished the month 16-13, which was good enough to tie for first. Despite going 17-10 in May, they didn’t get a share of first place again until June 1, but they spent that entire month atop the division — most of it with sole possession of first place — while going 16-11.

It was around that time that Corbin Carroll’s season started taking an unfortunate turn. On June 29 — the same day he was named as a starter for the National League in the upcoming All-Star Game — the 22-year-old outfielder left a 6-1 loss to the Rays after four innings, having experienced soreness in his right shoulder during a third-inning plate appearance. It was the same shoulder on which he’d undergone surgery to repair a torn labrum in 2021, which cost him nearly the entire season. In the wake of his removal from the game, he underwent strength testing, which showed that his shoulder was strong and stable, but the Diamondbacks gave him a breather, limiting him to a single pitch-hitting appearance over the next three days. After returning to the lineup, he played just three more games before leaving the team’s July 6 tilt against the Mets in the seventh inning, once again in pain. “I took a swing, and I felt a shift in my shoulder, shocking, tingling sensation go down my arm and then my hand go numb,” he told reporters. “I was just holding it thinking it came out of the socket, pretty much thought that the season was over.”

Despite his initial concerns, Carroll had not experienced a dislocation, and his MRI came back clean. He was back in the lineup the next day, and while he’s certainly had his moments since then — and hasn’t missed a game — his production and quality of contact are down considerably since the first incident:

Note that with two hits and two walks on Sunday, Carroll raised his post-July 1 wRC+ nine points; he was at 96 previously. Along the way, his swinging strike rate has spiked from 8.4% to 12.4%, and his chase rate from 28.8% to 32.6%, though his strikeout rate has barely budged, from 19.8% to 20.1%.

Maybe Carroll’s downturn in production is related to his shoulder woes, maybe it’s just the league adjusting to a player who looked like an MVP candidate early in the season, or maybe it’s just regression, more on which below. One way or another, it’s been poorly timed, in part because he’s not the only Diamondback who has tailed off in recent weeks:

Just four Diamondbacks have a 100 wRC+ or better since the start of July, one of them a catcher (Moreno) who has been limited to 11 of the team’s first 29 games in that span and is now sidelined by left shoulder inflammation. Moreno, Thomas, and McCarthy are the only three players with a higher wRC+ since the start of July than before, and they’re still below average offensively overall. Deadline additions Tommy Pham (from the Mets) and Jace Peterson (from the A’s) have yet to make an impact, going a combined 4-for-30, all singles.

Meanwhile, note that not only has Carroll fallen off steeply but so have Gurriel and Perdomo, both of whom joined him on the NL All-Star squad but might as well be on the side of a milk carton these days. Setting the narrative of Carroll’s shoulder injury to the side for a moment, this is striking:

All three players hit well above their Statcast expected stats through the end of June, particularly Perdomo, a slappy switch-hitter who doesn’t hit the ball hard at all; his season barrel rate is 1.2%, his hard-hit rate 19.9%. Then it’s as though the Regression Monster showed up and took a bite — each of these three players has seen about a 75-point swing in their wOBA-xwOBA differential.

Overall, the Diamondbacks hit .263/.330/.437 through the end of June, ranking fifth in the majors in scoring (5.11 runs per game) and seventh in wRC+ (106). Since then, they’ve hit just .227/.302/.373 while ranking 29th in scoring (3.44 runs per game) and 26th in wRC+ (83). Their performance against every major pitch type except changeups has fallen off by at least 50 points of SLG and 25 points of wOBA:

Yikes. They were punishing four-seam fastballs earlier in the season, but that’s stopped, and they’ve particularly gotten eaten alive by sliders and sweepers lately. What’s especially strange is the general downward trend of their more recent numbers despite the weather getting even warmer, which tends to increase offense. Of course, it’s as hot as the surface of Mercury in Arizona, so maybe the Diamondbacks have just wilted in the heat.

That does seem to be true with the team’s pitching, particularly the bullpen:

Good gravy. In writing about the Sewald trade — which sent Rojas and prospects Dominic Canzone and Ryan Bliss to Seattle — I noted that manager Torey Lovullo had been working with a matchup-based closer-by-committee system involving righties Miguel Castro, Kevin Ginkel and Scott McGough and lefty Andrew Chafin. However, I did not drill down to see just how bad things had gotten for them in the recent past. Using the July 1 cutoff again, with full awareness of the small samples in play, Ginkel has pitched well (0.75 ERA, 2.35 FIP in 12 innings), but the other three had been torched, with Castro (6.00 ERA and 6.60 FIP in 12 IP) the “best” of them, though he had stopped getting ninth-inning save chances, and Chafin (9.95 ERA and 5.63 FIP in 6.1 IP) and McGough (8.76 ERA and 6.91 FIP in 12.1 IP) utterly terrible. Chafin had two blown ninth-inning saves that led to losses in that span; he’s now a Brewer.

As for the rotation, it’s been pretty unstable, with Zac Gallen and rookie Ryne Nelson the only real constants, and both of them experiencing fall-offs since the start of July. Gallen pitched to a 3.02 ERA and 2.73 FIP in 104.1 innings through June, making his first All-Star team, but has yielded a 4.17 ERA and 4.12 FIP in 45.1 innings since, with his home run rate increasing from 0.6 per nine to 1.6. Nelson went from a 4.97 ERA and 4.44 FIP to a 5.59 ERA and 6.19 FIP, not that it should have been too surprising given his double-digit barrel rate even in the “good” times. Merrill Kelly, the team’s second-best starter, missed four weeks (most of July) due to a blood clot in his right calf but has been solid when available. Tommy Henry showed some improvement before being sidelined last week due to elbow inflammation. Brandon Pfaadt has been getting better results since being recalled on July 22 than prior, though his overall ERA of 7.11 in 44.1 innings is pretty damning. Also sporting an unsightly ERA (7.38) is Zach Davies, who has been dreadful on both sides of the divide while missing time with oblique and back injuries. Slade Cecconi, the team’s 2020 first-round pick, just made his major league debut on August 2 in place of Henry and acquitted himself reasonably well in a losing cause against the Giants, though his catcher (Herrera) had a rough time on the rookie’s first strikeout.

Given their current injury situation, the Diamondbacks now find themselves trying to stay afloat with just two starters who have demonstrated the ability to be league average or better, plus three rookies who have combined for a 5.63 ERA and 5.31 FIP. It’s not like the cavalry is on the horizon, either. The team’s playoff odds, which stood at 76.4% through the end of June (24.9% division, 51.5% Wild Card), are down to 21% at this writing, including just a 0.7% chance of overcoming their 8.5-game deficit to win the division. Considering that they lost 110 games just two seasons ago, they’ve certainly made progress to get to this point, but it seems quite apparent given their performance over the past five-plus weeks that they’re not quite ready for prime time.