Fred Chapman appeared in a game on July 22, 1887 when he was 14 yrs and 8 months old. I think he was the youngest ever. In more modern history, Joe Nuxhall pitched in a game in June 1944 for the Cincinnati Reds at the age of 15 yrs 10 months.
The youngest player to appear in the Premiership is Fulham's Matthew Briggs aged 16 years and 65 days.
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.
As of this writing, the youngest MLB player is Tigers pitcher Rick Porcello, Born 12/27/88
Jack Wilshire from Arsenal is 19 years old and the youngest player in the Barclays Premier League.
the youngest player to score a hat trick in the English premier league
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.
The youngest player ever to appear is: 18yrs 115days: Enzo Scifo (Belgium 2-0 Yugoslavia, 1984)
Fred Chapman was 14 and played 1 career game Joe Nuxhall was 15 and came back 8 years later to win 160+ games
So far, the answer will be Rick Porcello of Detroit Tigers, he is 21 years old