Bonus babies were amateur baseball players who received a signing bonus in excess of $4,000 and went straight to the Major Leagues between the years 1947 and 1965.
Major League Baseball teams aggressively bid against each other for young prospects during the late 1930s and early 1940s, a practice that resumed after World War II ended.
Signing bonuses literally skyrocketed during this period and the wealthiest teams were often able to sign many of the best players, sometimes just to stash them in their farm systems - a rule was put into place to stop these franchises (Cardinals, Dodgers, Red Sox and Yankees) and ultimately, limit labor costs.
Instituted by Major League Baseball in 1947, The Bonus Rule prevented baseball teams from assigning certain players to farm clubs. The rule stipulated that when a Major League Baseball team signed a player to a contract in excess of $4,000, the team was required to keep that player on the 25-man roster for two full-seasons.
Any team that failed to comply with The Bonus Rule lost the rights to that player's contract, exposing them to the waiver wire. If the player did remain with the team for a full two seasons, the team could then send that player down to their farm system without repercussions. The rule was abolished in 1965, after the amateur free agent draft was introduced.
A complete list of bonus babies appears below, in order by their Major League debut date, with bonus amounts, team data (amateur / big league), and links to their online baseball cards. Research by Baseball Almanac.
"Bonus Baby: A free-agent player signed under the bonus rule of 1953-1957. Such players were usually 18 or 19 years old, so full of talent and promise that they overshadowed their high school or college teammates and had professional teams scrambling to sign them; however, many bonus babies had failed careers as they were not ready for baseball at the major-league level and their talent rusted in idleness on the bench" - Dickson, Paul. Author. The Dickson Baseball Dictionary. W. W. Norton & Company. 13 June 2011. Page 125.
Did you know that five bonus babies — Al Kaline, Harmon Killebrew, Roberto Clemente, Sandy Koufax, Catfish Hunter — made it to the National Baseball Hall of Fame? Too easy? Which one of these five bonus babies was sent down to the minor leagues after their mandatory time was over? [Answer]
The amateur draft ended the bonus baby era, but some players were still able to (a) be drafted, and (b) go straight to the majors.
The Detroit Free Press | June 26, 1953 | Page 23
On June 25, 1953, the Tigers had two bonus babies debut in the same game at the same time, centerfielder Al Kaline & relief pitcher Bob Miller!