Joe Nuxhall, who pitched for the Cincinnati Reds in 1944 at the age of 15. The reason he was in the majors so young was because it was wartime, and with a large number of players in the military, rosters were extremely short. He wasn't very good, though- he got hit really hard and was sent down to the minors after his very first game. It would be eight more years before he made it back.
As of this writing, the youngest MLB player is Tigers pitcher Rick Porcello, Born 12/27/88
Rick Porcello is the youngest player in the MLB right now. He was born December 27, 1988. Fernando Martinez is the youngest in the National League. He was born October 10, 1988.
the blue jays
In 2014, the youngest manager in Major League Baseball was Mike Matheny. He is not the youngest however. He is the 14th youngest ever.
In 1974, Robin Yount became the youngest everyday player in baseball. He was 18 years old when he began his career with the Milwaukee Brewers.
So far, the answer will be Rick Porcello of Detroit Tigers, he is 21 years old
Clayton Kershaw, 20 Los Angeles Dodgers born March 19, 1988
Albert (Al) Kaline, Detroit Tigers, .340 at the age of 19.