5. Pitcher Pink Hawley (1892) 19 years, 252 days
Hawley had a 10-year career in the big leagues with the Browns, Pirates, Reds, Giants, and the original Brewers team in 1901.
He did not pitch particularly well in his three seasons in St. Louis, going 30-58 with a 4.45 ERA in 108 appearances with the team, including leading the league with 27 losses in 1894. That following season the Browns traded him to Pittsburgh.
4. Third basemen Kohly Miller (1892) 19 years, 251 days
Miller only played five major league games and just one in St. Louis. In 18 professional at-bats, he had 2 hits and 1 RBI. Understandably with how long ago Miller played, and how brief his career was, the information regarding Miller is very bleak. So bleak in fact that it is unknown what handedness he hit and threw with.
3. Pitcher Silver King (1887) 19 years, 95 days
King appeared in his first major league game with the Kansas City Cowboys as an 18-year-old before playing for the St. Louis Browns. He would go on to play 3 seasons with St. Louis where he saw his most success, especially in 1888.
That year he put up stats that we will never see again with how drastic the game has changed. He started a mind whopping 64 games in 1888 (all of them complete games) won 45 of those starts, and had a 195 ERA+, he threw 584.2 innings and tossed 6 shutouts, all of those stats led the league that season.
His 1.63 ERA in 1888 was the first of two ERA titles King won in his career, doing it again with the Chicago White Stockings two years later.
2. Pitcher Willie McGill (1891) 17 years, 174 days
Imagine playing in the big leagues before graduating high school. McGill actually made his MLB debut in 1890 with a team called the Cleveland Infants at just 16 years old.
The Browns purchased McGill from a team that was only in major league baseball for one season known as the Cincinnati Kelly's Killers in 1891. This was McGill's only season with the Browns as he won a career-high 18 games with a 2.70 ERA in 29 starts and 33 appearances.
1. Pitcher/Outfielder Nat Hudson (1886) 17 years, 96 days
Now there is some dispute about when Hudson was actually born, but based on the current date of birth that is found on Baseball Reference, Hudson was the youngest player to ever play a game for the St. Louis Browns in the 19th century.
In his age 17 season, he went 16-10 with a 3.03 ERA and won the pivotal game 5 of the World Series against the Chicago White Stockings, which led to the Browns winning the championship in 6 games. Hudson was also a part-time position player on days he did not pitch, as he appeared in the outfield, first base, and even shortstop during his career. He hit .247 with 3 home runs and 58 RBI in his hitting career.
Despite getting his career off to a good start at such a young age, he was out of baseball by the age of 20. During the 1890 season, Hudson was suspended by the team for insubordination and when he tried to dispute it, he was traded to Louisville and never played in the MLB again. The story about this and an overall biography of Hudson is explained in depth here. Let's now look at the 5 youngest players to appear in a game for the Cardinals in the 20th century.