Eddie Gaedel's August 1951 plate appearance

On August 19, 1951, the St. Louis Browns played a doubleheader against the Detroit Tigers. Browns owner Bill Veeck — known for promotional stunts — signed Eddie Gaedel (a 26-year-old, 3’7″, 65-pound performer) to a one-game minor-league contract. Gaedel was sent to pinch-hit for outfielder Frank Saucier in the bottom of the 1st inning of the second game wearing #1/8 (the smallest fraction). Tigers pitcher Bob Cain laughed openly on the mound, then walked Gaedel on four straight pitches. Gaedel was replaced by a pinch-runner.

American League president Will Harridge voided Gaedel’s contract the next day and barred such ‘spectacle’ contracts going forward. Gaedel’s plate appearance is the only one of his MLB career — he never appeared in another professional game. He died at age 36 in 1961. The 1951 jersey is in the Baseball Hall of Fame.

Excluding stunts: Bill Sherdel and Jose Altuve

The shortest MLB player to play a real career was Bill Sherdel, listed at 5’4″. Sherdel was a left-handed pitcher who played 15 seasons for the St. Louis Cardinals (1918-30) and Boston Braves (1930-32). He won 165 games, made the 1926 and 1928 World Series with the Cardinals (against the Yankees), and is one of two pitchers to start two World Series games at less than 5’5″ (the other was Bobby Wallace, also 5’4″).

The shortest player in modern MLB is Jose Altuve, the Houston Astros’ second baseman, listed at 5’6″. Altuve was the 2017 AL MVP — the only modern player under 5’7″ to win the award. He’s also a 9-time All-Star, 7-time Silver Slugger, the all-time hits leader at second base in Astros history, and a 2× World Series champion (2017, 2022). His MVP year was complicated by the Astros’ 2017 sign-stealing scandal disclosed in 2019.

Other notably short MLB players

Stubby Magner (Yankees, 1911) — 5’4″. Wee Willie Keeler (Hall of Famer, 1892-1910) — 5’4 1/2″. Joe Sewell (Hall of Famer, Cleveland/Yankees, 1920-33) — 5’6″. Hack Wilson (Hall of Famer, Cubs, 1923-34) — 5’6″. Phil Rizzuto (Hall of Famer, Yankees, 1941-56) — 5’6″. Freddie Patek (Royals, 1968-81) — 5’5″.

The pattern reverses for pitchers — extremely short pitchers are nearly nonexistent because the leverage and velocity advantages of being tall are overwhelming. There has never been an MLB starting pitcher under 5’7″ who started 100 games. By contrast, dozens of position players under 5’7″ have had long careers.

Background facts cross-referenced with the Wikipedia article on Eddie Gaedel and Pro-Football-Reference / Basketball-Reference public records.