The Nationals, here lining up for their final exhibition against the New York Yankees, have a young nucleus that not only makes them a perennial playoff contender but also a potential dynasty. (Jonathan Newton/THE WASHINGTON POST)

After midnight on Oct. 12, 2012, less than an hour had passed since the Washington Nationals’ season ended in wrenching defeat. Inside their clubhouse, Bryce Harper had already reckoned with his team’s collapse in a manner only youth allows. Harper, still a 19-year-old rookie, paused as he slowly filled a duffel bag on the floor with his belongings. “I’ve got 20 more years of this,” he said.

Even in a dark moment, the allure of what lay ahead for the Nationals surpassed the pain of the present. Monday afternoon at Nationals Park, that future will start to unfold. The Nationals will take the field against the Miami Marlins for opening day, their first meaningful action since losing Game 5 of the 2012 National League Division Series. They are carrying expectations not only of winning Washington’s first World Series since 1924, but of launching baseball’s next dynasty.

“I feel like the window is opening,” right fielder Jayson Werth said. “And it’s going to be open for a while.”

Before last year, the Nationals had not finished with a winning record in any season since baseball returned to Washington in 2005. After years of ineptitude and careful planning, the franchise’s vision exploded a year ahead of schedule, with a 98-win season and a National League East title.

“They’re clearly the team to beat in the National League,” New York Yankees General Manager Brian Cashman said. “They were the team to beat going into the playoffs last year. The best teams don’t always win. But on paper, I would say they’re the odds-on favorite in the National League.”

The Washington Post’s LaVar Arrington, Mike Wise, Liz Clarke, and Jonathan Forsythe predict whether the Nationals will exceed their MLB-best 98 wins in 2013. (Post Sports Live)

Under General Manager Mike Rizzo, the Nationals have designed a roster built for sustained success. The Nationals have 20 of the 25 players on their opening day roster under contractual control for at least the next three seasons, including four members of their starting rotation and seven of their eight everyday position players. The four Nationals selected to last year’s All-Star Game are aged 20, 24, 27 and 27. No one on their opening day roster is older than 33, and 19 are 29 or younger — either in or approaching their prime seasons.

“We’re going to be good for a long time,” reliever Tyler Clippard said. “A lot of the guys that are here now are here for multiple years, under team control for a while. That’s what makes this team special.”

Window of opportunity

In professional sports, as Washington fans have learned up close, even the most promising foundations can curdle. In 2008, the Capitals stunned the National Hockey League and surged into the playoffs. Homegrown superstars Alex Ovechkin, Nicklas Backstrom, Mike Green and Alexander Semin headed a limitless, youthful core. They stole the town’s attention and put the league on notice. They may have bowed out in the playoffs, but for two years they posted the best record in the sport and seemed to be a perennial favorite to collect a Stanley Cup.

Five seasons later, their window threatens to shutter, its potential unfulfilled. As his production has declined precipitously and inexplicably, Ovechkin’s 13-year contract no longer seems like the no-brainer of a deal it was when he signed. Green has spent much of the past three seasons injured. And Semin was allowed to leave as a free agent. Now, the Capitals are struggling to make the playoffs. They still have not reached the Eastern Conference finals, let alone won a championship.

Nationals officials focus their effort to ensure their World Series trophies, like those Stanley Cups earmarked for the Capitals, do not go unclaimed. As the Nationals rose from irrelevance to the top of baseball, Rizzo refused to allow the excitement of the moment cloud his long-term view.

“My job is to be kind of the soothing voice and the voice of reason and say, yes, we’ve got an opportunity now,” Rizzo said. “How long is our window? And what can we do to maximize our chances within that window? When I see the headlines or the talk shows saying we’re going for it this year — we went for it last year, we’re going to go for it this year, we’re going to go for it next year and the year after.”

When Rizzo took over in 2009, he and his top lieutenants studied organizations that had managed long-term success and compared them to teams who had won and then sputtered. He declined to share specific conclusions — “I don’t want to give out too much of our plan,” he said. But the exercise shaped how he built the Nationals from a 103-loss mess to a 98-win potential juggernaut.

“We’ve taken input from each model and tried to put together a philosophy,” Rizzo said. “We’ve had a really specific game plan and blueprint of how I wanted this thing to be going to go forward. So far, we’re hitting on most of the points and most of the important aspects we hit on years ago.”

The most crucial aspect has been the Nationals’ focus on the draft and player development. Rizzo and his staff predicted MLB would change rules to limit how teams spent to sign their draft picks when the league introduced a new collective bargaining agreement in late 2011. They insisted they should pour money into signing amateur players while there was still no spending cap, and also into resources — including staff additions — to develop those players.

From 2009 through 2011, when they drafted Stephen Strasburg and Harper with first overall picks given to them for having the worst record in the league, the Nationals spent more than $40 million to sign prospects they drafted. They used some of their minor league stockpile to trade for Gio Gonzalez, who finished third in the 2012 Cy Young vote, and new center fielder Denard Span. The Nationals have Gonzalez under contract through 2017; Span through the 2015 season.

Protecting the future

Perhaps the biggest pitfall for a potential power is injury. Bad luck can doom a franchise, but the Nationals have tried to guard against it.

When the front office started revamping of their medical protocols, they had no clear system of where to send a player for a specific ailment. Now they have a poster of a body — featuring starting pitcher Jordan Zimmermann’s head, chosen at random, on top — with arrows pointing at every body part and its corresponding doctor. They used suggestions from Werth to find nontraditional, cutting-edge specialists.

“Organizationally, if you want to win and you’ve got the guys to do it, I believe you should take care of them,” Werth said.

Temptation to forsake the future for immediate, short-term success can also strike. As their window opens, it is easy for the Nationals to predict they will act with prudence. But what happens if impatience — perhaps on the part of 87-year-old owner Ted Lerner — intercedes?

“Let’s just say your club has been in contention for a few years,” Detroit Tigers General Manager Dave Dombrowski said. “Now it’s [the trade deadline], and you’re trying to win. You’ve been there a couple years, and yet it takes that [prospect] to get that player. Well, that’s a decision you make at time. Do you trade that player that, even though it hurts your future, to get that guy that makes the difference to win this year?”

The Nationals received an early test last season, when Rizzo stuck to his plan to voluntarily shut down ace Strasburg for the stretch run. He determined, to great disparagement, that shelving Strasburg, two years removed from elbow reconstruction surgery, gave him the best chance to stay healthy in the years ahead.

“It was a very controversial move, a move that’s never been done before,” Rizzo said. “We took a lot of criticism for it. Again, it was in our long-term vision and our long-term plan. . . . We’ve done it before. We’ll do it after. This is the way we develop pitchers. This is the way we protect pitchers. To me, protecting and developing go hand-in-hand.”

And the Nationals have developed a minor league system worth protecting. “I just look at it and laugh,” said Vice President for Player Development Bob Boone, a baseball lifer who played catcher for 19 major league seasons. Boone has worked for the Nationals since 2005. He can recall when they filled the top levels of their farm system with veteran free agents, because none of their homegrown players had enough talent to compete.

Now, he said, the Nationals’ Class AAA outfield, all players developed from their system, may be better than their major league outfield from 2009. Infielder Anthony Rendon and center fielder Brian Goodwin, both of whom will start the year in Class AA Harrisburg, rank among the top 75 prospects in baseball.

“And,” Boone said, “wait until you see Giolito.” Lucas Giolito, the Nationals’ first-round pick from 2012, is an 18-year-old who was throwing 100-mph fastballs before he underwent Tommy John surgery.

Giolito’s estimated major league arrival is 2016. Depending on how the path he takes, and if he believes it will best preserve the Nationals’ future, Rizzo will limit his innings.

“It’s not, ‘We’re all in for 2013,’ ” Rizzo said. “We’re all in for 2013, but we also have the vision for 2013 and beyond because we want to sustain this, the success that we’ve had. We don’t want to be a one- and two-year and done type of franchise.”