WASHINGTON — When the Washington Nationals face the Los Angeles Dodgers in the NL Division Series, they’ll see a steady diet of left-handed hitters throughout the lineup.

Late in games, they believe that makes Sammy Solis the left man for the job.

The lefty reliever returned Tuesday from a five-week stint on the disabled list with shoulder inflammation and threw a perfect seventh inning against the Arizona Diamondbacks. Solis’ first appearance since Aug. 15 was a positive sign that he’ll be able to contribute in October.

“He was awesome,” manager Dusty Baker said. “He said he was ready. We threw him right in the fire. He showed us he was ready.”

Facing Socrates Brito, Jean Segura and Jake Lamb in a two-run game against Arizona in late September isn’t the same as going up against Dodgers lefties Chase Utley, Corey Seager, Adrian Gonzalez, Josh Reddick or Andrew Toles, but it was a high-leverage spot nonetheless. Solis appreciated Baker’s confidence in him in that situation with Cy Young Award candidate Max Scherzer’s 19th win and another step toward home-field advantage in the first round at stake.

Baker said the Nationals hadn’t yet decided on their 25-man roster, but they should have their bullpen stocked with lefties because of their opponent. After dealing Felipe Rivero to Pittsburgh for right-handed closer Mark Melancon, they acquired Marc Rzepczynski from Oakland and re-acquired Sean Burnett from Minnesota.

Still, bullpen depth has been an area of concern. Baker said the return of Solis is “a huge boost.”

“He’s the one lefty in the bullpen that can get lefties and righties out equally,” Baker said. “That’s big because you don’t have to change pitchers. We’re not going to have all these pitchers (like a September 40-man roster) when you get to the postseason.

“You’re going to have to let some righties face lefties and some lefties face righties or else you’ll go through your whole bullpen and you play extra-inning games you’ll be out of pitching. So that’s huge.”

Righties are hitting .229 and lefties .193 off Solis this season. In a perfect world for Washington, he could become a one-inning, doesn’t matter who’s batting reliever. Getting lefty Brito and righties Segura and Lamb out easily in his first game back was a small-sample-size indicator of that.

The 28-year-old only has 53 appearances in his career, all over the past two seasons with the Nationals. But he has only given up three home runs in that time, which could be a difference-maker in the playoffs.

Solis said Tuesday night he just hopes to make the playoff roster, which shouldn’t be an issue. And he wants to be counted on against the Dodgers no matter the role.

“We’re going to throw our best stuff at them,” Solis said. “I really hope I’m in there especially with a left-handed dominant lineup like they have and some power, as well.”