Rob Manfred was scheduled to throw out the ceremonial first pitch at Nationals Park on opening day, but in one of his best early decisions as Major League Baseball commissioner, he made a call to the bullpen.

On March 25, Manfred contacted Duane Dargin, a 9-year-old scholar-athlete in the Washington Nationals Youth Baseball Academy. The two had met before, when Dargin and three of his classmates traveled to Williamsport, Pa., for the Little League World Series last August, and again in February, when Dargin helped give Manfred a tour of the academy’s facilities.

“Mr. Manfred called and said that I could pitch the pitch for him,” Dargin said Monday after throwing a perfect strike — from the top of the mound, no less — to Ian Desmond. “He was joking around, but he said, ‘I’m a little too old to throw that ball.’ ”

Dargin, who attends Anne Beers Elementary in Southeast, put a hand in the air to acknowledge the 42,295 fans in attendance after his name was announced and Manfred dropped the ball in his glove.

“I was excited,” Dargin said. “I just couldn’t wait. I had a feeling that it was going to be a little bit off — just a little bit — but I was able to get it straight down [the middle].”

Dargin, a left-handed pitcher who aspires to play third base “because usually left-handers don’t play third base,” said he wasn’t the least bit nervous Monday. Seriously.

“I’ve played in front of large crowds of people,” Dargin said. “I’ve said ‘play ball’ for the Nationals before, so it’s nothing new.”

“Throwing out a first pitch is a very exciting thing,” Manfred said during a second inning visit with Bob Carpenter and F.P. Santangelo in the MASN broadcast booth. “The message we want our fans to get is, it’s about the kids. I had an exciting opportunity, rather than me doing it, I thought it was a nice symbol to let a kid do it.”

Dargin watched the game from Section 130 with several members of his family, including his parents, who offered some unnecessary advice before he stepped to the mound.

“[They said] don’t get mad if it doesn’t go your way, if I don’t get it straight down [the middle],” Dargin said.

Dargin was impressed with Max Scherzer’s Nationals debut in a 3-1 loss to the Mets, but Stephen Strasburg is his favorite member of the rotation. His overall favorite player, however, is outfielder Michael Taylor, whom he had the chance to meet last year when he shouted ‘play ball’ before a Nationals game.

“He’s a black player and usually black players don’t play baseball,” Dargin explained. “I want to play for the Nationals and he plays for the Nationals, and that motivates me even more to play baseball.”

Fans came up to Dargin to congratulate him on his first pitch and pose for photos. Manfred signed a baseball for him. And if he were playing middle infield in the sixth inning Monday, the opening day outcome might’ve been different.