Bryce Harper of the Washington Nationals bats in the 2011 XM All-Star Futures Game in July. (Jeff Gross/GETTY IMAGES)

Bryce Harper is big baseball news. Harper was the No. 1 pick by the Washington Nationals in the baseball draft last summer. He is big and fast, and he can hit the ball a mile. This summer, Harper is making his way through the Nationals’ minor league system.

Professional baseball teams have minor leagues for players who are not ready for the big leagues. There are four levels of minor league baseball: Rookie, Single A (A), Double A (AA) and the highest minor league level, Triple A (AAA).

Harper started this season in A ball, with the Hagerstown Suns. He was terrific, batting .318 with 14 home runs and 46 runs batted in (RBI) in 72 games.

So the Nats moved him to their AA club, the Harrisburg Senators, where Harper has struggled a bit so far. As of Wednesday, he was hitting just .238. He looked like a superstar, however, when I saw him play the Bowie Baysox last week. Harper had three hits and blasted his first home run for the Senators.

Harper is a big deal because he’s so young. At just 18, he is playing with guys who are five, even 10 years older.

Washington fans are hoping Harper makes it to the majors and starts smashing home runs for the Nationals next season. But baseball is a tough sport. It’s unusual for a teenager to play in the majors and even more unusual for a teen to hit bunches of home runs.

Here is a list of some players who hit a lot of home runs in the majors at age 19. It’s a short list, which tells you how rare it is for a player to do what Harper seems to be on track for. The chart below shows batting average, home runs and RBI for some star 19-year-old big leaguers.

Mel Ott (1928) .322 18 77
Mickey Mantle (1951) .267 13 65
Tony Conigliaro (1964) .290 24 52
Ken Griffey Jr. (1989) .264 16 61

Ott and Mantle each slugged more than 500 home runs in their Hall of Fame careers. Griffey slammed 630 homers and is a shoo-in to be elected to the Hall of Fame when he becomes eligible in 2016.

Conigliaro led the American League in home runs with 32 when he was just 20. Sadly, Conigliaro’s career was cut short when he was hit in the face with a fastball in 1967. The injury affected his sight, and he retired a few years later.

So keep a close watch on Harper. Who knows: He might make it to the big leagues as a teenager and hit home runs, just like Mickey Mantle, Tony Conigliaro and Ken Griffey Jr.

If he does, that will be really big news.

Fred Bowen is the author of 17 sports books for kids, including eight books about baseball.