Left-handed pitchers are employed at the major league level to, at the very least, get left-handed hitters out. But Nationals reliever Sammy Solis didn’t fit the standard profile last season. Left-handed hitters batted .355 in 34 matchups last season, while right-handers managed only .255 in 60 plate appearances. Flummoxed, he devoted time to figuring out how to rectify the oddity.

“That was a big focus this offseason and spring training, learning how to get inside on lefties and mixing it up against them,” the 28-year-old Solis said. “And finding the right, I guess, repertoire, with my three pitches to get them out.”

The adjustments were rewarded: Left-handed batters hit .200 off Solis in 66 matchups this season, and he maintained his success against righties (.218 in 106 plate appearances).

Solis’s ability to get both righties and lefties out makes him an indispensable weapon in the postseason, one the Nationals weren’t sure they would have after a stint on the disabled list that ended until Sept. 26. His shoulder healthy, Solis is certain to make Washington’s roster for their National League Divisional Series against the Dodgers. He and the Nationals’ other left-handed relievers could be the difference in the best-of-five series that begins Friday at Nationals Park.

Like most playoff teams, the Dodgers are well-rounded, but they have one glaring weakness: hitting left-handers. The Dodgers ranked last among 30 teams in batting average, on-base percentage, and slugging percentage opposite southpaws. One reason: Five of their best hitters – Corey Seager, Adrian Gonzalez, Chase Utley, Joc Pederson and Andre Ethier – are left-handed. The Nationals have one left-handed starting pitcher — Gio Gonzalez. The other southpaws will come out of the bullpen.

“The thing is, despite the numbers, we’re not going to take them lightly,” Solis said. “With the power that they have from the left side as well, they can do damage, no matter the situation, no matter the count. So yes, they might have trouble hitting lefties but that doesn’t mean we’re going to go up there thinking ‘oh, we got this, no problem.’ We’re still locked in and we’re ready to go because if you make one mistake against these kinds of hitters and that can change the entire the postseason, it can change your entire season.”

The Nationals have options to capitalize on the flaw. The team’s other lefties are Marc Rzepcyznski, Oliver Perez and Sean Burnett. Dusty Baker declined to reveal his bullpen for the series, but said the team will carry three left-handed relievers. According to a person familiar with the situation, Burnett is the odd man out.

Rzepcyznski, who joined the Nationals at the end of August, had the best numbers this season and boasts the most playoff experience. In 70 games for the Oakland Athletics and Nationals, he had a 2.64 ERA in 47⅔ innings. Since joining the Nationals at the end of August, he had a 1.54 ERA in 11⅔ innings. His 67.4 percent groundball rate was second in baseball among relievers who logged 40-plus innings, and he held left-handed hitters to a .674 OPS in 113 plate appearances. He has a 4.22 career playoff ERA in 18 games across three postseasons.

“I think this year I’ve just been able to keep the ball down for the most part,” Rzepczynski said. “And keeping my sinker down for righties and throwing my changeups and having them roll over instead of them hitting it to right field and giving them another pitch to see that they haven’t seen in recent years. Just keeping the ball down.”

Current Dodgers are a combined 8 for 33 in 38 plate appearances against him. Utley is 3 for 12, Gonzalez is 4 for 6 with a home run, Seager is 0 for 5 and Ethier is 0 for 5.

Perez, 35, made 64 appearances and had a 4.95 ERA in 40 innings, though he hasn’t allowed a run in his past 11 outings. In 102 matchups, left-handed hitters posted a .720 OPS. Perez has pitched in two postseasons, one as a starter in 2006 with the New York Mets and last season as a reliever with the Houston Astros. Perez has held current Dodgers to a combined .226 batting average. Gonzalez is 4 for 24 with a home run, Utley is 4 for 26, Ethier is 1 for 14, Pederson is 0 for 4 with three strikeouts and Seager is 0 for 2.

The 34-year-old Burnett appeared in just 10 games with the Nationals after spending nearly the entire season in the minors with four organizations. He had a 3.18 ERA in 5⅔ innings and held lefties to a .500 OPS in 14 matchups. He was in the Nationals’ bullpen for the 2012 postseason, totaling one inning across two appearances and allowed four runs, three earned.

He has the best career numbers of the three choices against current Dodgers: 3 for 33 in 39 plate appearances. Utley is 2 for 12, Gonzalez is 0 for 6 and Either is 0 for 4.

“The matchup part of it is important, but the performance part of it also important,” Nationals General Manager Mike Rizzo said. “I’m not gonna take a lesser player just because he has one set of skills like left handed if you’re not performing. It’s well-documented that left-handed pitching is important here, but you need to have quality pitches because I’ve seen [the Dodgers] many, many times, live in person and on film for countless hours, that if you don’t have stuff and you don’t perform, they can beat you left-handed or right-handed.”