LOS ANGELES — The Los Angeles Dodgers played one of their sloppiest defensive games of the season, ending it with a botched home run by Chicago Cubs center fielder Pete Crow-Armstrong. But Tuesday night gave them an undeniable dose of optimism — Yoshinobu Yamamoto returned after a three-month layoff and his stuff looked sharper than ever.

Before the Dodgers lost 6–3, cutting their division lead to 4½ games, Yamamoto limited the Cubs to just one run in four innings of work, during which he struck out eight batters. His fastball averaged more than 96 mph. His splitter and curveball looked devastating. His command was as sharp as anyone could reasonably expect, considering that he had not pitched in a major league game since injuring his rotator cuff on June 15.

“It was pretty surprising,” Dodgers catcher Austin Barnes said. “I didn’t know what he was going to look like after that game, and he looked better than he ever did.”

The Dodgers have struggled with injuries in their rotation all season and entered Wednesday with just one regular: Jack Flaherty, who was scheduled to start for them in October.

But then Tyler Glasnow, who has been out since Aug. 11 with what the team described as tendonitis in his elbow, threw his second bullpen session, prompting his coaches to clear him for a two- to three-inning simulated game on Friday.

And Yamamoto looked a lot like the player the Dodgers had in mind when they gave him a 12-year, $325 million contract this offseason, the largest ever for a starting pitcher.

“I feel a lot better about the rotation tonight than I did 24 hours ago,” Dodgers manager Dave Roberts said. “It’s starting to turn around in terms of getting back to the rotation that we envisioned.”

Yamamoto began his outing with three consecutive strikeouts: Ian Happ hit a curveball into the dirt, Dansby Swanson hit a splitter that landed just below the strike zone and fellow American Seiya Suzuki hit a full-count fastball that hit the outer edge of the plate.

The Cubs scored a run in the second inning after shortstop Miguel Rojas and first baseman Freddie Freeman mishandled ground balls. But Yamamoto struck out the side again when the Cubs lineup turned the ball over in the top of the third inning, ending his outing by allowing former Dodgers prospect Michael Busch to turn an inning-ending double play in the fourth.

Yamamoto said through an interpreter: “Today’s outing went much better than I expected.”

He threw 59 pitches and is expected to reach about 75 pitches when he gets his turn Monday, when he has three more starts to prepare for the playoffs.

“We’re going to take that every start — fastball command, both sides of the plate, hits the low dart, the split under there, steals a strike with the breaking ball,” Roberts said. “It was really good.”