Dodgers starter Clayton Kershaw overpowers the Nationals on Tuesday night. (Stephen Dunn/Getty Images)

Faced with an already depleted lineup and opposed by the best left-handed starting pitcher in baseball, Davey Johnson played a hunch. He figured, why not? With Jayson Werth on the disabled list, Bryce Harper in the Washington Nationals trainer’s room and Clayton Kershaw on the mound, Johnson removed his leadoff hitter, too. He put Denard Span, fully healthy, on the bench and gave Eury Perez the first start of his career. Johnson put his faith in long odds.

Johnson’s gamble yielded predictable results in a 2-0 loss to the Los Angeles Dodgers. Kershaw carved through a lineup that included a starting outfield that would seem out of place in the Grapefruit League, let alone Dodger Stadium on a cool mid-May night. Kershaw struck out 11 Nationals in 82 / 3 overpowering innings, yielding only five hits as he threw a career-high 132 pitches and lowered his ERA to 1.40.

“He’s an unbelievable pitcher,” shortstop Ian Desmond said. “He’s the best in the game, in my opinion.”

Despite being so thoroughly dominated, Dan Haren kept the Nationals in the game and, somehow, they could have tied it in the ninth inning with one swing. With two outs, Adam LaRoche singled to end a 10-pitch at-bat. Dodgers Manager Don Mattingly marched to the mound and, drenched in boos, hooked Kershaw. Reliever Kenley Jansen came in and simply whiffed Tyler Moore, the Nationals’ 12th strikeout of the night.

Moore, who also struck out with the bases loaded in the first inning, made the most glaring outs Tuesday night. But he had company. Second baseman Danny Espinosa went 0 for 4 with three strikeouts, dropping his average to .175 on the season as he tries to fight out of a 2-for-25 slump. As a team, the Nationals finished with a .230/.292/.370 slash line.

The Post Sports Live crew talks about Bryce Harper’s collision with the right field wall Monday night at Dodgers Stadium. (Post Sports Live)

“There’s a few guys on the ballclub who are not doing the things they’re capable of doing,” Johnson said. “They’ve been struggling off and on all year and we just need to right the ship. I know it’s been an issue. There’s progress. The middle of my lineup’s doing a lot of good things. But some of the other guys are not doing the things they’re capable of doing.”

The Nationals’ flailing rendered the continued resurgence of Haren moot. Coming off three consecutive wins, Haren allowed just two runs on four hits in seven steady innings. Over his last four starts, Haren has lowered his ERA from 7.36 to 4.76. With the Atlanta Braves losing in Arizona, the Nationals could have surged into a first-place tie in the National League East for the first time since April 6.

Haren pitched through a minor scare. In the fifth inning, Haren pulled up short as he attempted to cover first base on a groundball, forcing LaRoche to sprint to the bag. Haren’s left foot caught on the mound, and as he rolled his ankle, pain shot up his leg and into his back. Last year, back problems landed Haren on the disabled list.

Haren walked gingerly back to the mound, where head athletic trainer Lee Kuntz and pitching coach Steve McCatty visited him. Haren stayed in, though, and retired the final seven batters he faced.

“I’m 100 percent fine,” Haren said. “Obviously, I’ve hurt my back before, so it scared me at first. It didn’t tighten up or anything throughout the game. I felt just as good in the seventh as I did in the first.”

Haren’s only mistake came in the third inning. Kershaw led off and Haren hit him in the foot with a two-strike cutter. Haren rolled his eyes and looked to the sky, knowing he had made a potentially crucial error. After Carl Crawford flied out and Matt Kemp singled, Haren erred again, throwing a wild pitch that moved both runners into scoring position.

Haren whiffed Adrian Gonzalez with a chest-high, 88-mph cutter. One more out, and he would keep the game scoreless. Andre Ethier, a left-handed hitter, walked to the plate with first base open. But Johnson did not want Haren pitching with the bases loaded, and anyway, Haren feels just as comfortable facing lefties.

Still, Haren knew he could be careful with Ethier. He started him with two pitches out of the zone, the second of which Ethier swung through to make the count 1-1. For the next pitch, Haren intended to throw a splitter in the dirt. Instead, it remained up and over the plate. Ethier lashed it up the middle, and Kershaw and Kemp cruised across home plate to give the Dodgers a 2-0 lead.

“Going against a guy like Kershaw, you have to be perfect,” Haren said. “And I wasn’t perfect.”

Kershaw needed nothing more. He can make any lineup appear feeble with his mid-90s fastballs and preposterous curveballs. Heaters seem to suddenly appear in the catcher’s mitt, and curveballs disappear.

Johnson had used a lineup that could rightly be filed under, Just So Crazy It Might Work. Steve Lombardozzi, Moore and Perez — two infielders by trade and a 22-year-old who had never started a major league game — started in the outfield. Espinosa, batting .181 coming into the game, hit leadoff. Desmond, normally the No. 6 hitter, moved to the cleanup spot.

“Against a pitcher of this caliber, a lot of times I throw guys in off the bench,” Johnson said.

It did not work. The Nationals managed five hits all game, all singles, three of them from third baseman Ryan Zimmerman. Espinosa’s struggles were the most pronounced. In his first three at-bats, he struck out three times while seeing 11 pitches.

“The guy has a 1.40 ERA and he strikes out 10 every game he pitches,” Espinosa said. “He didn’t make many mistakes. He didn’t make any mistakes to me over the middle. Everything was corner to corner. It happens. There’s nights like that when he’s throwing better pitches than you can handle. He just threw a good game.”

The Nationals’ impotence Tuesday night underscored one of their lineup’s issues this season and hinted at the potential troubles they would face should Harper miss more than a handful of games in the aftermath of his collision with the outfield fence. The Nationals have played consistently with a key starter missing — just as Zimmerman came off the disabled list, Werth went on it. And now, as Werth prepares to return Saturday, Harper faces the prospect of playing through bruises and bumps all over his body.

Last season, the Nationals thrived because their reserves ably filled in. This year, they are treading water, in part, because their bench hasn’t delivered. In the most pivotal moment of Tuesday night, the one time the Nationals made Kershaw vulnerable, one of those bench players stumbled.

The Nationals forced Kershaw to throw 29 pitches in the first inning, but the work only led to frustration. Two-out singles from Zimmerman and Desmond followed by a walk from LaRoche loaded the bases. Kershaw then dispatched Moore with a four-pitch strikeout, blowing fastballs by him and then tricking him with a diabolical curveball. Moore this year is 0 for 4 with three strikeouts with the bases loaded, and overall he’s hitting .145.

“With two outs, against anybody in the big leagues, it’s tough to get that hit,” LaRoche said.

Against Kershaw, maybe the best in the game, that hit never came.