Players attempting to play in MLB often choose not to defect to the United States, because establishing residency in the United States means they must enter the MLB Draft . If they defect to another nation, they can become free agents , allowing them to choose their offer.  The largest contract given to a Cuban defector is outfielder Rusney Castillo 's seven-year contract with the Boston Red Sox , signed in 2014, worth $ million.  First baseman José Dariel Abreu signed a six-year contract worth $68 million with the Chicago White Sox in 2013.  The largest contract given to a pitcher was the $32 million the New York Yankees gave to José Contreras in 2002,  while the Cincinnati Reds signed Aroldis Chapman for $ million in 2010. 
But rule isn’t in place to stop practical jokers. What ultimately did the tradition in was how unsafe it is to have a foreign object on the baseball field, and how likely it was for an idly-lying glove to change the outcome of a game. You can pretty easily imagine a player trying to line up under a popup and instead tumbling over the opposing shortstop’s glove; that can lead to an injury and an error, both of which are best avoided. While the rule was a bit controversial when enacted — like many other rule changes, tradition weighed heavy — it gained acceptance shortly thereafter, and today, is taken for granted.