He undoubtedly left the fans at Scottsdale Stadium talking about the exploits of baseball's teenage Paul Bunyon.
Harper finished 1-for-4 with a two-run double Wednesday and spent 10 minutes following the 6-3 victory by his Scottsdale Scorpions signing autographs for fans of all ages.
"I've been around that my whole life," Harper, 18, said. "It's been like that since I was 13, 14 years old so it's just another day at the park."
Harper's first at-bat had the fans at the park smiling. The phenom hit a sky-high fly on the first pitch he saw from Mesa Solar Sox starter Josh Zeid in the second inning and as if on cue, it began to rain as soon as shortstop Andrew Romine caught the ball for the out.
spring chickens/fall league
The sky cleared up by the time Harper resumed his position in right field for the top of the third inning. He later cleanly fielded a single off the bat of Mets prospect Josh Satin as if the grass were as dry as cardboard.
Those in attendance chuckled at the fantasy of Harper's fly making it rain. Reality set in during the seventh inning when Harper smashed a ground-rule double to left field, narrowly missing a grand slam to one of the deepest parts of the stadium by only a few feet.
"I felt really good at the plate and I was not really jumpy at all. I didn't feel overmatched at all," Harper said. "They came after me and I really appreciate that. I thank all of them for coming at me and facing me with the fastball and offspeed."
In his second at-bat, Harper swung and missed at the first two pitches -- both breaking balls -- before lining out to center on a fastball on the third pitch in the fourth inning. In his third at-bat, Harper took a pitch for a strike before grounding out on a sharply hit ball to third base on the second pitch.
"It was a lot of fun to come out here and step up my game a little bit," Harper said. "It's a lot of fun to come out and face 92-95 [mph] everyday. I got a few pitches I could drive and did what I did."
It's only been one game but Harper says he's already having a blast. He could be the biggest star to play in the Arizona Fall League but he is by no means the first.
There have been more than 3,000 players pass through in the AFL since the six-team league was formed in 1992 and more than 1,800 have reached the Major Leagues. Fifty-one alums of the AFL are still playing in the postseason for the Rangers, Yankees, Giants and Phillies.
The 2010 Arizona Fall League's media guide itself is a testament to its star power. The cover photo features the AFL's Class of 2009: Atlanta's Jason Heyward, Florida's Mike Stanton, Chicago's Starlin Castro, San Francisco's Buster Posey and fellow Washington up-and-comer Stephen Strasburg.
Including Harper, 35 first-round Draft picks are currently playing in the Arizona Fall League. Still, this year's class is unlike any other in recent history.
"I'm not sure we've ever had a player this young receive this much attention," said Steve Cobb, the executive director of the Arizona Fall League. "We're talking about a young man that's already been on the cover of Sports Illustrated as an amateur. There is a lot of interest and I think it's a great story to capture him at the infancy of could be a very prolonged Major League career."
The ties between the Arizona Fall League and the big leagues were everywhere Wednesday. Among the tidbits in the evening's media notes was a special recognition of Rangers outfielder Josh Hamilton, who played for the Maryvale Saguaros in 2001, as the Arizona Fall League alumni of the day. Hamilton, who is hitting .316 with four home runs in the ALCS, is considered a favorite to win the AL Most Valuable Player. He met Harper last July during All-Star week in Anaheim.
"The biggest thing I told [Harper] is be happy and thank the Lord that you have this opportunity to do what you want to do and play the game you love," said Hamilton, himself an overall No. 1 pick, in 1999. "At the same time, no matter what happens -- whether you're the first pick, the 50th pick or a 30th-round pick -- humble yourself realizing that you don't know everything, realizing that there a lot of people who have been playing this game a long time that can help you."
Harper has already shown progress since being selected by the Nationals with the first overall pick in the 2010 First-Player Draft last June. He hit .319 with a .407 on-base percentage for the Nationals in the instructional league, leading the team in hits, home runs, RBIs and walks. He is expected to start the 2011 season at Class A.
After the game, Harper admitted that he felt more pressure making the jump from high school to junior college ball than the leap to the AFL because of the expectations that were placed upon him.
"There's always going to be steps," he said. "Going to junior college was a step. You are always trying to get better in the game and you try to get bigger, faster and stronger in the offseason. They are all steps to where you want to be when you are older."
Jesse Sanchez is a national reporter for MLB.com. Follow him @JesseSanchezMLB on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.