From BR Bullpen
- For a list of Bonus Babies, please see the List of baseball players who went directly to the major leagues.
The Bonus Rule was instituted by Major League Baseball in 1947 to prevent teams from assigning certain players to farm clubs. The rule stipulated that when a Major league team signed a player to a contract in excess of $4,000, the Major League team was required to keep that player on the 40-man roster for two full-seasons.
Any team that failed to comply with the rule lost the rights to that player's contract. The player was then exposed 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 the farm teams without repercussions. The rule went through several variations until it was finally abolished in 1965.
 History of the rule
In the late 1930s and early 1940s, Major League franchises found themselves bidding against one and other for the services of young players. These engagements subsided when a real war, World War II, broke out. When the war ended, the bidding wars resumed.
This competition for the best amateur athletes resulted in skyrocketing signing bonuses. In 1947, Major League Baseball implemented the Bonus Rule. The rule prevented the wealthiest teams from signing all of the best players and from stashing those players in their farm systems. Additionally, the bonus market was weakened as a result of inhibited competition. In return, this limited labor costs.
The legitimacy of the rule was challenged several times after it was initially implemented. In December of 1950, the rule was rescinded. In 1952, a committee chaired by Branch Rickey revived the rule. It was this iteration of the rule that stated a team had to place the players who met the Bonus Rule criteria on the Major League roster immediately. Furthermore, the player had to remain on the roster for two calendar years from the signing date. Although the players were signed as a result of their potential, some players were not able to succeed. Pitcher Tom Qualters appeared in one game in the 1953 season. He did not appear in another game until 1957.
The New York Yankees worked out a deal with the Kansas City Athletics where the A's signed Clete Boyer to a contract. The A's used him sparingly for the two years they had him and then just days after the point when they could send Boyer down to the minor leagues, they traded him to the Yankees as the "player to be named later" from a trade concluded the previous winter. This trade did not sit well with the owners of the other American League teams. They claimed that the Yankees had used to the A's to hold Boyer. However, the deal was allowed by the league.
Incidents like the Clete Boyer trade showed how the Bonus Rule could be circumvented. On top of that, rumor spread that teams were ignoring the rule and bribing players. In 1958, both leagues voted to rescind the rule. In addition, they rescinded it retroactively. This eliminated the major league roster requirement for the players signed in 1957.
After the league added four new teams, the Bonus Rule was reintroduced in 1962. The difference between the new version of the rule and the previous one was that a player had to spend just one full season on the roster instead of two seasons, and this season could be delayed under certain circumstances.
In June of 1965, the Major league draft was introduced in baseball. Each drafted player was required to negotiate with the team that selected him. This brought an end to the Bonus Rule.
 Bonus babies
Players who received a signing bonus in excess of $4,000 during that era have been identified as 'Bonus Babies'. In accordance with the Bonus Rule, when a player who had received more than $4,000 in bonuses entered into a contract, the players' Major League team was required to keep that player on the 25-man roster for a full season. This prevented the player from spending time in the Minor League baseball system that is and was the training ground for most professional baseball players in the United States.
- Treder, Steve. Cash in the Cradle: The Bonus Babies. hardballtimes.com. Retrieved on 2006-11-15.
 Further Reading
- Wynn Montgomery: "Georgia's 1948 Phenoms and the Bonus Rule", in The Baseball Research Journal, SABR, Volume 39, Number 1 (Summer 2010), pp. 72-82.
- Sam Zygner: "Phillies Bonus Babies, 1953–57", in Morris Levin, ed.: From Swampoodle to South Philly: Baseball in Philadelphia and the Delaware Valley, The National Pastime, SABR, 2013, pp. 92-97.