Harper’s father, an ironworker named Ron, told him, “It’s the same game you’ve been playing your whole life.” Bryce Harper spent 7½ long hours on a plane before he touched down at Los Angeles International Airport at 1 a.m. He spent the flight, his last moments before playing in the major leagues at 19, gathering his thoughts and reflecting. The scouts who watched him play at 13 years old, the Sports Illustrated cover at 16, leaving high school early, it had all led to this.

“It was good to be able to sit back and really figure out what was going on and really take everything in,” Harper said. “There’s no words for it.”

Manager Davey Johnson thought Harper seemed relaxed before the game. He walked into the dugout and faced a 40-member media contingent, which included no fewer than four cameras, including one filming a documentary. His back scraped against the wall as he sat on top of the bench. In the background, Nationals owner Mark Lerner snapped a photo with his camera phone.

“I’m actually not very nervous right now,” Harper said. “I thought I’d have a different reaction to everything. I thought once my coach called me in, I’d ball up a little bit. But I didn’t. I’m just trying to take it all in. I think once they announce my name and I see my name, I think it’ll really hit me.”

Harper’s parents, sister and more than two dozen family members and friends traveled the roughly 3½ hours from their home in Las Vegas to attend the game. Harper did not even know how many had come. “My parents made a list,” he said. His brother Bryan, a left-handed pitcher in the Nationals farm system, had a game and could not make it. Neither could General Manager Mike Rizzo — he attended the White House Correspondents Dinner as a guest.

Harper, at 19 years 195 days old, became the youngest player in the major leagues since 2005, when Seattle Mariners right-hander Felix Hernandez took the mound at 19 years 123 days old.

Harper’s stay in the majors is “more than likely not going to be permanent,” said Scott Boras, Harper’s agent. Rizzo planned for Harper to receive between 250 and 300 at-bats in Class AAA, but an injury to third baseman Ryan Zimmerman altered those plans. The Nationals needed a hitter, and Harper was the best they had.

“I’m worried about what the game does to players,” Boras said. “I don’t think the game particularly likes young players coming in. I think it wants to show them there’s something going on up here that’s a little bit different than anywhere else you’ve ever played.”

Johnson advocated for Harper to make the Nationals out of spring training. He believes Harper has come to the major leagues to stay, that his talent will not let him down. Johnson said that mentally, the major leagues may be easier than the minors.

“Bryce is so driven, a lot of times he tries to do too much just getting here,” Johnson said. “Sometimes, just getting here is kind of like more relaxing. This is what he’s been after since probably he was 12 years old. He sights have been on playing in the major leagues. He’s much more driven than anybody I’ve ever seen.”

Saturday afternoon, Harper met Boras, at the entrance to Dodger Stadium. As they walked up the tunnel and the field became visible, Harper looked at Boras and told him, “The grass is still green.” The ability level would change, but the game would not.

Harper’s red, No. 34 batting practice jersey hung in his locker, between Henry Rodriguez and bullpen catcher Julian Martinez. Five lockers separated his from Stephen Strasburg’s. Three hours before the first pitch, Harper sat at the stool in front of his stall and scribbled a few words, which he kept private, underneath the brim of his cap.

In his first round of batting practice, Harper blasted three balls halfway up the pavilion beyond the right field fence in six swings. In his second round, Harper smashed a line drive that nearly knocked over the fence in left-center. The crowd gasped. The ball off his bat sounded like gunfire. “Pretty impressive,” said Bo Porter, the coach pitching to him.

About a half-hour before first pitch, the arriving crowd cheered when the public address announced Harper’s name, batting seventh and playing left field.

“Bryce may say he doesn’t like it,” Johnson said. “But I think he likes the attention.”

As shadows crawled across the outfield, Harper emerged from the Nationals dugout, his gray pants pulled up to his knees, revealing bright red socks. He finished off his warmup, sprinting in shallow right field, stretching with all the other big leaguers.

“I guarantee this is exactly the way he played it out in his head since he was 10 years old,” shortstop Ian Desmond said. “He’s been dreaming about this for so long that I think nothing will take him by surprise.”