done." On August 26, 2010, Harper was introduced by the Nationals. He said he chose to wear No. 34 because "I always loved Mickey Mantle, three and four equals seven." After batting .319 with a .407 OBP (and leading his team in hits, home runs, RBIs, and walks) in the Nationals' fall instructional league, Harper was selected to participate in the Arizona Fall League (AFL) as a member of the Scottsdale Scorpions taxi-squad, the second-youngest player in the history of the league (two days older than when Mets' prospect Fernando Martínez appeared in the league in 2006). He batted .343 and slugged .729. On November 20, Harper and the Scottsdale Scorpions won the 2010 AFL Championship. After batting .399 in spring training, Harper began his minor league career when the Nationals optioned him to the Hagerstown Suns of the Class-A South Atlantic League. In April 2011, after a slow start in the minor leagues, Harper visited optometrist Dr. Keith Smithson, who reportedly told him, "I don't know how you ever hit before. You have some of the worst eyes I've ever seen." In his first 20 games after receiving contact lenses, Harper hit .480, collecting seven home runs, 10 doubles and 23 RBIs. Harper was selected to represent the United States in the 2011 All-Star Futures Game during the 2011 All-Star Game weekend. He was promoted to the Harrisburg Senators of the Class AA Eastern League on July 4. Harper went 2-for-3 in his AA debut with two singles, a run, and a walk. On August 18, 2011, Harper injured his hamstring while running from second to third on an extra-base hit. The injury was severe enough for him to be carried off the field by his coaches. He was placed on the seven-day disabled list and the injury ended Harper's season. Harper began the 2012 season with the Syracuse Chiefs of the Class AAA International League. Washington Nationals (2012–2018) 2012 season: NL Rookie of the Year The Nationals promoted Harper to the major leagues on April 27, 2012, after Ryan Zimmerman was placed on the disabled list. He made his MLB debut with the Nationals the next day against the Los Angeles Dodgers. Harper grounded out to pitcher Chad Billingsley in his first major league at-bat. He recorded his first major league hit, a double, in his third at-bat against Billingsley and got his first RBI on a sacrifice