Juan Jose Soto.
As a 19 year old, finished runner up in the National League Rookie of the Year voting as he put together one of the most historic seasons for a teenager in MLB history (see info boxes below)...Began his season with Single-A Hagerstown before getting promoted to Single-A Potomac on April 23 and to Double-A Harrisburg on May 10...Appeared in just eight games with the Senators before having his contract selected on May 20...Clubbed a three-run home run in his first at bat the next day, May 21 vs. San Diego (Erlin)...Not only did he rank among the top National League rookies, but from May 15 (the first game in his game log, due to the suspended game vs. NYY) through the end of the season he ranked among all National League hitters in walks (T4th, 79), on-base percentage (5th, .406), runs (T6th, 77) and OPS (8th, .923)...Moreover, among all National Leaguers (min. 490 PA), he ranked in on-base percentage (2nd, .406), OPS (3rd, .923), slugging percentage (10th, .517) and batting average (12th, .292)...Finished his rookie season with a .292 batting average, .406 on-base percentage and a .517 slugging percentage...He is just the 15th rookie in Major League history - and the only teenager - to finish a season with that slash line...His .406 OBP placed him in exclusive company with 2017 AL Rookie of the Year Aaron Judge and 2001 National League Rookie of the Year Albert Pujols (.403 in 2001)...Since 2001, Soto, Judge and Pujols are the only rookies to post an on-base percentage greater than .400 in their rookie season (min. 400 PA)...Named NL Rookie of the Month for June, July and Sept...On June 13, recorded the first multi-home run game of his career with a three-run blast in the fourth inning and a go-ahead solo home run in the seventh inning to help the Nationals top the Yankees at Yankee Stadium... He became the fifth-youngest player in MLB history to record at least two home runs in a game...He joined ATL Andruw Jones (10/20/96), SEA Ken Griffey Jr. (5/30/89) and CWS Brian McCall (9/30/62) as the only teenagers since 1962 to record multi-HR games on the road against the Yankees... Went on to record two more multi-home run games (6/29 at PHI and 9/11 at PHI)...Posted a 21-game on-base streak from Aug. 24 to Sept. 16...Hit .370 (30-for-81) with four doubles, five homers, 19 RBI and 15 walks during the streak...His 21-game on-base streak tied HOF Mickey Mantle and trailed only HOF Mel Ott (22 games in 1928) for the longest on-base streak by a teenager in MLB history...With three stolen bases on Sept. 15 at Atlanta, he became the youngest player since 1900 to steal three bases in a game, besting Rickey Henderson (20 years, 241 days)...Following the season, took part in the 2018 Japan All-Star Series...Hit .350 (7-for-20) with two doubles, two homers, five RBI, two walks and six runs scored in five games