Coaches and players huddle up after practice at the Nationals Youth Baseball Academy, which hopes to lure District youths back to the sport. (Bill O'Leary/The Washington Post)

In late September, the ball settled into Denard Span’s glove for one of the last outs of the Washington Nationals’ triumphant regular season, and Rafael Scott — one of the few African American fans in Section 311 — looked down at his young seatmate.

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“He’s out, Grandpa,” declared D’Angelo Scott, 9. “The center fielder caught the ball.”

“You’re learning, D, you’re learning,” said Scott, 64, satisfied that he was an inning closer to fulfilling an increasingly tough generational duty: passing on the love of baseball he’d learned from his own father and grandfather.

That wasn’t so hard in the days when African American communities buzzed with the box scores of the Washington Senators and the Homestead Grays, back when kids in dusty lots mimicked the basket catches of Willie Mays and the base-running banditry of Jackie Robinson.

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Back before baseball all but vanished from the playgrounds, televisions and back-fence chatter of black neighborhoods.

Now, old-timers such as Scott hope a dose of pennant fever will give them another crowbar to loosen the iron grip of the NFL and the NBA on young attention spans. Surely, with Span, one of the few African Americans on the Nats’ roster, having a breakout year and the team a favorite to reach the World Series, some little heads will be turned.

And yet, lean over and ask a city kid like D’Angelo — even as he basks in the green infield glow — what his favorite sport is, and he’ll answer instantly: “Football!”

“It’s a tough sell, for sure,” said Antonio Scott, D’Angelo’s uncle and the general manager of the D.C. Grays, a summer collegiate league team. “They think it’s boring to watch on TV; they don’t see too many players that look like them. Having a winning team helps, but it’s not enough.”

Baseball’s decline among African American youth is a long-standing concern of the sport, from top to bottom. And it’s lost favor among adults, too.

In a 2011 Post poll of Washington area residents, just 3 percent of African Americans cited baseball as the sport they follow the most, while 74 percent favored football and 13 percent basketball.

In the decades since Jackie Robinson broke baseball’s color line in 1947, the share of African American major league players has also plunged, from a high of 18.7 percent in 1981 to 8.3 percent in 2014, according to Major League Baseball and the Society for American Baseball Research.

The Post Sports Live crew debates whether the Nationals will be disappointed with anything less than a World Series title after the end of an incredible regular season. (Post Sports Live/The Washington Post)

In response, the league has issued reports and launched task forces. In March, the Nationals opened a $17.7 million Youth Baseball Academy in Southeast Washington’s Fort Dupont Park with the goal, according to its director, of “creating a culture of baseball east of the Anacostia River.”

Span, a 30-year-old center fielder, views inspiring young African Americans as a sacred duty.

“I feel like God put me on this platform for a reason, and one reason is to be a role model for black kids,” Span said.

Several times a season, Span invites groups of youngsters who are growing up with a single parent, as he did, to come see him take batting practice and stay for a game. Before a recent outing, about a dozen boys and girls from area Little League teams — most of them African American — joined Span in a meeting room outside the clubhouse.

These kids were already fans. (“Can I have your hat, Denard?” one young outfielder asked Span, who laughed, signed his brim and handed it over.) But he knows that when he appears in front of most young African Americans, he’s just another grown-up.

“A guy coming off the bench in the NBA,” he said, “they’ll probably recognize him over an everyday baseball player like me.”

Washington’s fan-in-chief remembers when it wasn’t so. Mayor Vincent C. Gray, 71, started playing ball at age 8 in a D.C. where every recreation center had a team and pro players came to give clinics for kids who were hardball-crazy. Gray wore the number 8 from second grade through college in honor of Senators first baseman Mickey Vernon.

“Baseball was huge,” said Gray, who still plays softball weekly. He supported the return of major-league baseball to the city and the publicly funded $690 million Nationals Park, in part because it would serve to reintroduce the sport to communities that once embraced it.

“We lost touch with our adult role models,” said Gray. He’s ordered the city’s Wilson Building bathed in red light to mark the playoff series and thinks the deeper the Nats go, the more young African Americans will follow. Even those who bleed Redskins burgundy.

“Winning matters, and right now the winning team is the Nationals,” Gray said. “Our football team obviously has a ways to go.”

Robert Powell, who owns a janitorial supply company in Southeast, agrees. An avid Senators fan growing up, he began taking his grandson, Colby, to Nats games six years ago. Game by game, he teased out the subtleties for him, when to bunt, where to throw with runners on first and third and one out.

Colby, now 12, is smitten. He’s on a Capitol Hill youth team and was riveted not only by the Nats’ march to the postseason, but also by the performance of Jackie Robinson West, an all-black Chicago team, during the Little League World Series in August.

“Baseball has become a fixture with this kid,” said Powell, who has e-mailed the mayor’s office in hopes of bagging tickets to a playoff game for Colby and his teammates. “They will come, they will come. Because black folks love winners.”

The most visible sign of baseball’s effort to win over local kids is the gleaming modernist building surrounded by state-of-the-art ball fields just off Minnesota Avenue in Southeast. The Nationals Youth Baseball Academy was part of the city’s original deal to lure the former Montreal Expos to town, and critics complained when it took nine years to open with funding from the city and the team’s charitable foundation.

Now, in the program’s first year, 108 third-, fourth- and fifth-graders arrive by bus each day after school. (The academy plans to add a grade each of the next three years.) At no cost to their families, the kids pick up a snack in a demonstration kitchen where they also get nutrition lessons, do homework in supervised classrooms and then hit the fields for at least an hour a day.

It’s obvious that most of the students have had little previous experience with baseball. One boy said he would like to watch the Nats on TV but doesn’t have cable service at home. Another can name Span, Ian Desmond and Michael Taylor as his favorite players, but he knows of only one bat and one ball among the friends on his block.

“Nobody is into baseball where I live,” said Dwayne Dargin, 9, a fourth-grader at Beers Elementary.

Tal Alter, the former Haverford College shortstop who runs the academy, said he sees very little ballplaying in the surrounding parts of the city. Kids don’t have the gear, there’s not much green space, and parents don’t want their children out unsupervised.

“The truth is there is not a lot going on,” said Alter, 38. “The days of playing stickball in the street are gone.”

He hopes to fill the void with a safe place to play, good coaching and a supply of real ball for them to watch. Several high schools play at the facility, along with the Howard University women’s softball team and the D.C. Grays in the summer. Nationals players, including Span and Desmond, are frequent visitors.

There are signs that the presence of a winning professional team is starting to penetrate the consciousness of brains already crammed with images of RGIII and LeBron. The District’s recreation department reported a jump in participation for T-ball, machine-pitch baseball and softball this summer. The number of Little League teams in black neighborhoods is up.

Akili Cooper is a medical supply salesman who is trying to instill a love of baseball in his 7-year-old son. He thinks baseball is safer, in spite of being a serious football guy; he played for both Louisiana State and Howard universities, and his first cousin is Redskins wide receiver DeSean Jackson. The Nats are helping the cause, he said.

“The other day he made a good catch [for his Little League team] and someone called him Denard Span,” Cooper said. “He really liked that. Their success is definitely having an impact.”