and the youngest to ever make it to the final round. Harper hit his 17th homer of the season on August 6, the 39th of his career, passing Ken Griffey Jr. for most home runs by a player younger than 21. Only two other players hit more home runs than Harper before turning 21. In 118 games, he hit .274/.368/.486 with 20 home runs, 58 RBIs, and 47 extra base hits. During the 2013 off-season, Harper successfully underwent left knee surgery to remove a bursa sac. 2014 season During a game against the San Diego Padres on April 25, 2014, Harper suffered a left thumb injury when he slid into third base on a 3-run triple. He was placed on the 15-day disabled list the next day. An MRI revealed that the thumb had a torn ulnar collateral ligament. On April 28, it was announced that Harper would require surgery to repair the ligament tear in the thumb. During a rehab game with the Double-A Harrisburg Senators on June 28, Harper hit 3 home runs in a single game. Harper returned to the Majors on June 30. In 100 games during the season, Harper batted .273 with 13 home runs and 32 RBI. After the 2014 season, Harper planned to travel to Japan to participate in the 2014 Major League Baseball Japan All-Star Series, but later withdrew. 2015 season: First NL MVP On April 18, 2015, Harper hit the longest home run of his MLB career with a 461-foot drive over the center field wall against the Philadelphia Phillies. On May 6, Harper hit three home runs in a single game for the first time in his career. He did it against Tom Koehler, with one of the shots going 442 feet to the second deck in a 7–5 victory over the Miami Marlins. He became the youngest player to accomplish this feat since Joe Lahoud in 1969. Harper was later awarded the Player of the Month Award for May for the first time in his career. Measured by adjusted OPS (OPS+), Harper's 2015 was a top-5 hitting season (since 1900) for all players under the age of 23, and the best season of any hitter since Barry Bonds a decade earlier. He also led the majors in WAR and tied for the NL home run title with 42. Harper also became the youngest player ever with at least 40