Ross Detwiler and Kyle Lohse squared off in a pitching rematch of Game 4 of last year’s National League Division Series, and this time Lohse got the better of Detwiler and the Nationals. (John McDonnell/The Washington Post)

If the Washington Nationals are going to make the much-anticipated, still-absent run that validates their expectations, they first need to find a launching point. This week seemed to provide the ideal moment. Bryce Harper returned Monday, the Nationals scored double-digit runs in consecutive games and the Milwaukee Brewers would remain at Nationals Park for another three days. The Nationals, at last, would take off.

The perfect conditions have yielded the same disappointing results, all spinning wheels and no progress. The Nationals fell back to .500 Wednesday night with their 4-1 loss to the Brewers, avoiding consecutive shutouts only because Anthony Rendon drilled a solo home run into the visitors’ bullpen in the seventh inning. Kyle Lohse carved through the Nationals for eight innings, and the 23 runs they scored Sunday and Monday felt more like a blip than a spark.

“I don’t have any answers,” Manager Davey Johnson said. “Just kind of nothing. Can’t get nothing going. It’s putting me in the loony bin.”

Lohse and Ross Detwiler squared off in a pitching rematch of Game 4 of last year’s National League Division Series, and this time Lohse won. He gave up four hits and one walk and struck out seven. Detwiler, meanwhile, allowed four runs in six innings, two of them scoring after Harper dropped a line drive.

Once Lohse exited, the Nationals threatened. Ryan Zimmerman singled and Ian Desmond drew a two-out walk in the ninth off Francisco Rodriguez to bring Rendon to the plate as the tying run. The crowd rose as Rendon drilled a deep flyball to center field, but he knew right away he had not hit it far enough. The drive died on the warning track, and roars turned to groans.

“It’d be nice if we could score 13 runs a game,” said Rendon, a rookie batting .313. “But that’s just not how baseball is.”

As Zimmerman and Desmond walked off the field, the Nationals’ deficit in the National League East grew to 71 / 2 games. The Atlanta Braves lost to the Miami Marlins, which pushed their lead down to seven, sparing the Nationals from matching their largest gap of the season.

The Nationals will manage at best a split of their four-game series against the Brewers, who had gone 18-37 during the two months before they arrived Monday at Nationals Park. Washington will hand the ball on the Fourth of July to 24-year-old Taylor Jordan, who will make the second start of his career with an 11:05 a.m. first pitch.

Tuesday night, the Nationals wasted Stephen Strasburg’s seven-inning masterpiece. Wednesday night, they offered Detwiler no help as he carried a shutout into the fifth inning. Detwiler, like Strasburg before him, used his curveball with a higher frequency than usual, striking out three Brewers in the second inning, all on curves.

In the fifth, though, Detwiler stumbled. His fastball started to rise, and the Brewers started to belt it. Norichika Aoki ripped a two-run single to center, the Brewers’ third hit of the inning giving them a 2-0 lead.

“When it was time to make a pitch, I didn’t,” Detwiler said. “I kind of threw the ball straight down the middle.”

During his last start, Detwiler had experienced stiffness in the left side of his lower back. He said he felt better Wednesday, but he received treatment for nearly an hour after the game.

“It’s a long season,” Detwiler said. “You’re going to have your bumps and bruises and everything. I definitely felt better today than the last one.”

Aramis Ramirez began the sixth inning with a line drive to left field, more or less right at Harper. Tuesday night, in the eighth inning, Harper had dropped a flyball on the warning track that helped the Brewers tack on two extra runs. Now, the wall posed no threat. But as the ball screamed toward Harper, he dropped to a knee and awkwardly stabbed at it. The liner deflected off his glove.

“It was hit pretty hard,” Johnson said. “It could have been knuckling. You never know.”

Jonathan Lucroy followed with a single. Detwiler recorded two quick outs, but Logan Schafer smacked a two-out triple to right-center field. Ramirez and Lucroy trotted home, both runs unearned.

The misplay provided a reminder that Harper, who played catcher as an amateur, remains relatively new to left field. He learned to play center and right field in the major leagues last year. The Nationals switched him to left this spring, but he moved back to right after Jayson Werth sustained a hamstring strain. As a professional, Harper has still played only 81 games in left field.

Wednesday night, Harper’s drop continued an irritating day. In the first inning, he launched a drive to the warning track in center field. Carlos Gomez made a leaping catch to end the inning, and Harper slammed his helmet on the infield dirt.

In the fourth, Harper roped a line drive to left-center, a likely double until Gomez streaked across the outfield and snared it. Harper stopped between first second base and doffed his helmet toward Gomez.

The appreciation would turn into frustration for the rest of the Nationals. They had given themselves a chance to assert themselves, and they instead produced more of the same waiting.

Nationals notes: Catcher Wilson Ramos will return Thursday after missing the last 43 games with a left hamstring strain. Ramos will start, Johnson said. He went 0 for 3 as a designated hitter Wednesday night at Class A Potomac. . . .

Dan Haren is scheduled to come off the disabled list Tuesday and start against the Philadelphia Phillies, Johnson said. Haren threw roughly 70 pitches in a simulated game Wednesday afternoon. He has been on the disabled list since June 25 with inflammation in his right shoulder. “I’m getting the ball to where I usually do,” Haren said.