The Post's Jorge Castillo and Chelsea Janes preview the NLDS between the Nationals and Dodgers. (Jayne Orenstein/The Washington Post)

When Reynaldo Lopez made his major league debut in July, Washington Nationals Manager Dusty Baker told him he could play a role like Francisco Rodriguez. Lopez isn’t the baseball historian Baker is, and didn’t know anything about Rodriguez.

So Baker set about educating his new charge on how Rodriguez, as a 20-year-old rookie setup man for the Anaheim Angels, buzzed through Baker’s San Francisco Giants in the 2002 World Series.

“He said I could be like him,” Lopez said.

Lopez was just 8 years old then, and while the 25-man roster for the Nationals’ division series against the Los Angeles Dodgers is not yet official, he likely will be one of several rookies at center stage between the two clubs. The Dodgers’ roster, announced Tuesday, will feature seven rookies. The Nationals’ roster might not be far behind.

Rookies Pedro Severino, left, and pitcher Reynaldo Lopez, right, consult with pitching coach Mike Maddux. Both rookies are expected to see action in the National League Division Series against the Dodgers. (Nick Wass/AP)

Center fielder Trea Turner and catcher Pedro Severino will be in Friday’s starting lineup for Game 1 at Nationals Park. Sammy Solis, still technically a rookie at age 28, is the team’s best left-handed reliever, and Lopez will play the role of long reliever. Infielder Wilmer Difo and outfielder Brian Goodwin are candidates for bench spots. Right-hander Koda Glover has been hampered by a hip injury but could become an option if the club advances.

None of the seven rookies was on the Nationals’ Opening Day roster. Six months later, each could make an impact in the postseason.

“We take a lot of pride in that as young guys,” Turner said. “A lot of us had different years, up, down. Some of us didn’t think we would be here. Some of us did. It’s just a mix of everything. But it’s just a matter of taking advantage of your opportunities and getting those W’s, especially in the postseason.”

After switching to center field and becoming an everyday player after the all-star break, Turner has sparked the Nationals. He batted .342, slugged .567, hit 13 home runs, tallied eight triples and stole 33 bases. If not for Dodgers shortstop Corey Seager, Turner would be the favorite to win the National League rookie of the year award.

Severino’s rookie season was not quite as glamorous. The Nationals’ catcher of the future, he anticipated watching the playoffs on television until Wilson Ramos tore the anterior cruciate ligament in his right knee Sept. 26.

“It’s good to hope for opportunities to show what you have, but it’s difficult to get it like this, with Wilson getting hurt,” Severino said. “I feel bad. Really bad. But now it’s my job to help this team win.”

Severino will platoon with Jose Lobaton to replace Ramos and, as the right-handed hitting option, is expected to start the first two games against Dodgers left-handers Clayton Kershaw and Rich Hill. Severino, 23, does not possess Ramos’s slugging prowess, but he is an energetic and capable defender lauded for his preparation.

“A veteran does have a better idea on what he wants to do, but that’s why we have the pregame meetings and how we’re going to protect the hitters,” Baker said. “But Severino, what’s impressed me probably most is his ability to recall what the game plan is and how to make adjustments.”

Severino has caught Game 1 starter Max Scherzer once: On Aug. 3 against the Diamondbacks, Scherzer allowed three runs and had 11 strikeouts in eight innings. At the plate, Severino went 2 for 3 with a walk in an 8-3 victory.

“He’s a great low-ball framer,” Scherzer said. “He gives you a great, low target in the zone and it just feels like it’s just so easy to throw the ball down in the zone with him. It feels like he gets you an extra strike or two because of that.”

Difo, Goodwin, and Ben Revere are competing to join Chris Heisey, Stephen Drew, Clint Robinson and one of the catchers on the bench. A switch-hitter, Difo would provide speed and a right-handed bat to help balance left-handed hitters Robinson and Drew, and he can play three infield positions. Goodwin and Revere are both left-handed hitters but can play all the outfield positions. While Goodwin has been better at the plate in a smaller sample size, Revere has the longer track record and playoff experience.

“I tell all the rookies it’s okay to be nervous, just don’t be scared,” Baker said. “The game, the first pitch of the game, it’s okay to be nervous. It’s natural. If you’re not nervous, then you’re not feeling the energy that’s going to be in the stadium. It’s like being a gladiator kind of. You’re going to be nervous because you’re going to be out there, even though we’re hundreds of years past that point, still the stadiums are built like the Roman coliseums.”

Goodwin said there were times during the season, usually before batting practice while stretching, when he and Turner would wonder, “What if?”

“They got to get to know us sometime,” Goodwin said. “I mean, if the postseason is when it is then that’s when it is. It’s not like it hasn’t happened before. If that time comes and it happens to be one of us, I don’t see one of us missing.”