With six home runs and 13 RBI in four games, Bryce Harper is one of the most dangerous hitters in baseball. Post Sports Live discusses why Harper is finally playing up to his potential. (Post Sports Live/The Washington Post)

Baseball marvels at what Bryce Harper is doing this season: his growing patience at the plate, his power and on-going maturation into one of the game’s best hitters. In a superhuman display last week, the 22-year-old became the youngest player in major league history to hit six home runs over three games. “I’ve been in baseball for 34 years and I’ve never seen a run like he’s been on hitting the ball in the seats,” Washington Nationals hitting coach Rick Schu said.

But for Harper, his play is almost routine. When he is fully healthy, he is dominant. He terrorized pitchers in high school, college and the minor leagues. So to lead the majors in walks (30) and runs (29), and rank second in on-base-plus-slugging percentage (1.119), home runs (12) and RBI (31) entering Thursday? He expects that. Six homers in three games?

“I’ve done it before,” he said, sitting in the dugout before a recent game. “I’m not saying that to be cocky at all, but I’m saying that I want to do that again. I don’t want that to be the last time I do it.”

Through six weeks of the season, Harper has undoubtedly been the Nationals’ best player and among the best in baseball. Harper was already very good – his .816 OPS through his first three seasons was historic for his age — but this season, he is developing into a better outfielder and an elite hitter.

A confident Bryce Harper reported to Nationals spring training in Viera, Fla. When asked about adding Max Scherzer to the starting rotation, he said, “I just started laughing. I was like, where’s my ring?” (The Washington Post)

“We’re seeing him grow up right in front of our eyes,” Nationals starter Max Scherzer said.

But Harper thinks that explanation doesn’t tell the whole story.

“This is what I was like in high school and college,” said Harper, who twice had four-homer games at the College of Southern Nevada, where he hit 31 homers in 66 games in 2010. “That’s what people don’t understand. I was healthy. Staying healthy is what I need to do. This is the type of player I need to be and the type of player I want to be. Everybody talks about how I’m doing this different or I’m doing that different. There’s nothing different. It’s staying healthy and staying in the lineup. Truly.

“. . . I know it is way different here than in college and high school but if you look at all the stats I had in college and high school, they were absurd because I was in the lineup every single day. I played every day. I played year-round. I had the reps, I had the stuff, and I was never hurt. I was never hurt at all.”

Harper suffered his first significant injury, a hamstring strain, in 2011 at Class AA Harrisburg. In 2013, he hurt his left knee running into the right field wall and needed offseason surgery. Last season, he needed surgery on his left thumb after diving into third base. He still produced while averaging only 109 games each of the past two seasons, but not like now.

“I feel like the approach, the plan, it’s always been there,” Harper said. “But I’m finally sticking to it because I’m not getting hurt and staying healthy. It’s allowing me to stay in the games every single day and staying with my routine every single day and not getting sidetracked because I’m hurt and out a game and play two and then out for a month and a half and come back and play.”

Harper’s goals this season are 150 games and 600 at-bats. He has adhered to his pregame routine of stretching, running and throwing. He lifts weights — heavy but low repetitions — once a series. “That helps me a lot,” he said.

The Nationals are finally improving on their below .500 start to the season. Post Sports Live debates whether the team is playing up to its potential. (Post Sports Live/The Washington Post)

In his fourth season in the majors, Harper is also calmer — despite Wednesday’s ejection for arguing a called third strike. In Monday’s 11-1 win over the Arizona Diamondbacks, Harper went 1 for 4 with a walk, hitting the ball hard but at outfielders. On the bench, he fumed. He said to himself: “Dude, come on. You should’ve been 4 for 4 today or 3 for 4 today.”

In the past, his anger at himself might carry over into the next at-bat or the next game. Instead, he calmed himself, focusing on the hit and walk.

“I just want to be so good,” said Harper, who went 2 for 3 with a walk and an impressive two-run home run the next day. “But at the end of the day, did you win the ballgame? Yes. You get to come back the next day and do what you do.”

With the help of Manager Matt Williams, Harper has calmed his swing, improved his rhythm and simplified his approach. With a less jumpy lower body, Harper’s head is more still as he swings, helping him better recognize pitches. As a result, he can be more selective, swinging at a career-low 30.2 percent of pitches outside the strike zone and a career-high 87.3 percent contact with pitches inside the strike zone, according to FanGraphs.com.

“He’s just starting to realize that he’s so strong that, if everything syncs up, he just has to get a barrel on it and it’ll take care of itself,” Schu said.

Harper said he “absolutely” loves plays for Williams because he was such an accomplished hitter. Before every game, Harper asks Williams how he would attack that day’s opposing pitcher and his thoughts on Harper’s approach. “Having him around has been a lot of help,” Harper said. Williams’s advice in spring training still resonates.

“He looked at me and said, ‘It’s not how far, it’s how many,’” Harper said. “You can get a ball out of the field that’s 375 and hit it 376. It still counts the same. You can hit a ball 900 feet. It still counts the same as 300 feet.”

Harper doesn’t like talking about the mechanics of his swing. He has pulled more balls to right field, hit fewer balls on the ground and smashed previously troublesome pitches — change-ups and sliders. He knows teams have attacked him a lot outside but he has exploited that; his .833 slugging percentage on pitches on the outer half and away is the third highest in baseball, according to BaseballSavant.com. By keeping it simple and staying healthy, Harper is thriving.

“It’s really staying with the approach, staying with my mentality up there and every single day going about my business the right way and staying in the lineup,” he said. “That’s why I told [people] a million times if I stay in the lineup and do what I need to do I’ll be fine. If that’s me hitting .285 or me hitting .330. I just know I need to go up there with the same approach every single day and do what I need to do to help this team win.”