The Los Angeles Dodgers came into Thursday night as baseball’s winningest team, but they left Chase Field with plenty of questions—particularly about Yoshinobu Yamamoto. In a 5-3 loss to the Arizona Diamondbacks, the prized right-hander suffered his worst start of the season, giving up five runs across five shaky innings.

“Wasn’t as sharp as he’s been,” manager Dave Roberts said bluntly after the game, summing up the outing with trademark honesty.

Yamamoto, who had been dominant through his first seven starts in MLB, entered the night with a sparkling 0.90 ERA. But things unraveled in a hurry during the fourth inning. After allowing a leadoff walk to Pavin Smith and an infield single, Yamamoto hit Eugenio Suárez to load the bases with no outs. He then fell behind 2-0 to Gabriel Moreno and left a cutter up in the zone. Moreno made him pay, launching a grand slam into the right-field seats for his first homer of the season.

The Dodgers were suddenly down 4-0, and the deficit grew when Ketel Marte took Yamamoto deep in the fifth on another elevated cutter, making it 5-0.

D-backs slam Yoshinobu Yamamoto, Dodgers

Los Angeles Dodgers starting pitcher Yoshinobu Yamamoto (18) throws against the Atlanta Braves in the second inning at Truist Park.
Brett Davis-Imagn Images

“I think we’re the best division in baseball,” Roberts said of the NL West, which features four winning teams. “I don’t think anyone is gonna run away with it.”

Yamamoto’s line—five earned runs on six hits with four strikeouts and one walk—doubled his ERA to 1.80 and marked just the second time he allowed multiple home runs in a game. He was also pitching on five days’ rest for the first time this season, as the Dodgers continue to monitor his workload.

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On the other side, Diamondbacks starter Brandon Pfaadt turned in his best outing of the year, throwing 6 1/3 scoreless innings while striking out six. Jalen Beeks and the Arizona bullpen held off a late Dodgers push, and closer Kevin Ginkel sealed the win despite a Shohei Ohtani solo homer in the ninth.

“We just didn’t execute enough,” Roberts added. “You tip your cap to Moreno. He got a good swing on a mistake.”

The Dodgers threatened in the eighth inning, scoring twice to trim the lead. Max Muncy smacked an RBI ground-rule double, and rookie Andy Pages added an RBI single. But with the tying run on base, Michael Conforto grounded into a back-breaking double play, ending the threat.

It was a tough night all around for the Dodgers, who have now dropped three of their last five games. Still, with plenty of season left, Roberts emphasized patience over panic.

“You don’t win the World Series, or the division, in May,” he said. “It’s about staying the course.”

That course, however, just got a little bumpier with more division showdowns looming—and with their ace proving he’s human after all.