WASHINGTON — At the Washington Nationals’ home opener in April, Duane Dargin, 9, stood in the center of the diamond beneath sunny skies waiting to throw out the game’s ceremonial first pitch.

Just one year earlier, Dargin had never before held a regulation baseball in his hand, nor had he played baseball a day in his life. Dargin’s neighborhood, predominantly African-American and near some of the poorest sections of Washington, is like many urban areas in America where even the children’s parents cannot recall the last time there was a Little League game down the street.

“No one even knows the rules of baseball,” Dargin said.

It is one of the reasons that only 8.3 percent of players on Major League Baseball rosters last year identified themselves as African-American or black, a 50 percent drop from 20 years ago.

But on this day, before an announced 42,295 fans, Dargin, who is African-American, toed the pitching rubber, cocked his arm in a full windup and released, hoping for a strike.