Dodger Stadium was eerily quiet for much of Monday night. And not just because whole sections of the upper deck sat largely empty.

In a 9-5 loss to the Arizona Diamondbacks, the Dodgers didn’t just drop their fourth straight game, but turned in a performance that elicited as many boos as anything else at Chavez Ravine, stumbling to a season-worst losing streak on a night they did little right in any facet of the game.

There was bad defense early. In the first inning, center fielder Hyeseong Kim lost a fly ball in the twilight sky, leading to two runs that would have been unearned had it not been ruled a double. In the second, third baseman Max Muncy spiked a throw to first on a slow-rolling grounder that led to another preventable score, even though his miscue was also ruled a base hit.

The pitching wasn’t great either. Left-handed opener Jack Dreyer followed Muncy’s bad throw with an even wilder pitch to the backstop in the next at-bat, advancing the runner to set up an eventual sacrifice fly. Landon Knack took over in the third and promptly gave up a pair of two-run home runs, one to Lourdes Gurriel Jr. on a down-and-in slider and another to Gabriel Moreno on an inside fastball.

Even the few bright spots offensively weren’t close to being enough.

Mookie Betts hit two home runs in his continued search to break out of a slow start. Shohei Ohtani retook sole possession of the major league lead in long balls by whacking his 17th of the season. But all three blasts came with no one on base. And they represented the Dodgers’ only hits of the night against Arizona right-hander Brandon Pfaadt, who was otherwise unbothered in a six-inning effort that included no strikeouts (or even a single swing-and-miss from a Dodgers hitter) but plenty of fine plays from an athletic defense behind him.

“It’s hard to start games behind before you take an at-bat,” manager Dave Roberts said. “We’ve given up runs in the first inning. We got to put up that zero and kind of get a chance to get the game going.”

While shaky defense and inconsistent production at the plate have been bugaboos for the Dodgers (29-19), it is the team’s increasingly pitching struggles that have stood out most during this four-game skid — the club’s longest since losing five in a row in late May last season.

With the loss to the Diamondbacks (26-22), the Dodgers own a team earned-run average of 4.28, which ranks 22nd in the majors and is their highest at this point in a campaign since 2010.

The main root of the problem is easy to identify. Starters Tyler Glasnow, Blake Snell and Roki Sasaki remain on the injured list, forcing the club into plans such as Monday with a rookie in Dreyer opening for a depth arm in Knack. The bullpen has been shorthanded, too, with Blake Treinen, Evan Phillips and Kirby Yates all injured, as well.

“You go through certain situations like this, it’s just tough to find a way to get back healthy and get our guys back out there,” Betts said. “But we’re battling with what we got.”

Arizona’s Gabriel Moreno, right, celebrates with teammate Josh Naylor after hitting a two-run home run in the third inning Monday.

(Kyusung Gong / Associated Press)

The good news is that several of those sidelined options are on the mend. Glasnow and Snell are both progressing in their throwing programs, with Glasnow “a tick ahead of Blake,” according to Roberts. Sasaki is expected to begin his throwing program during the team’s upcoming road trip. And Ohtani, who has been throwing regular bullpen sessions all season, is beginning to build up his pitch count as the club targets his return to the mound sometime around the All-Star break.

But in the meantime, the Dodgers have still expected more from their currently healthy group.

“It’s not the staff we thought we’d have this season, but I feel that what we still do [have], and have done in the past with injuries, we’re not doing,” Roberts said. “In the sense of getting ahead of hitters, and keeping them in the ballpark.”

And to do that, Roberts cited one place to start.

“On first glance, we need to be better at getting ahead in counts,” he said. “It doesn’t take a deep dive to see we start 1-and-0 quite often. When you do that, it makes pitching tough.”

Indeed, the Dodgers entered the night 24th in the majors with a 59.8% first-strike rate, a problem Roberts believes has led to too many long innings, and too large a workload for the staff.

“The 30-pitch innings just don’t play. It’s not sustainable,” he said. “And that starts with getting strike one. That ultimately goes to our entire pitching staff.”

The Dodgers were better in that area Monday, starting 27 of 49 at-bats with a strike. But it didn’t help. Dreyer needed 38 pitches to get through his two innings. Knack threw 106 to get through the next five (including 16 in one at-bat to Moreno in the fifth).

And when long reliever Matt Sauer took over in the eighth and gave up a two-run home run to Geraldo Perdomo, much of a season-low (and atypically quiet) crowd of 41,372 began streaming for the exits, not sticking around for one of the Dodgers’ flattest showings this year.