Larry Bird Signs 5-Year Deal with Boston Celtics

Celtics retained their exclusive right to sign him until the 1979 NBA Draft, because of the NBA's "junior eligible" rule that existed at that time (allowing a collegiate player to be drafted when the player's original "entering" class was graduating and giving them one calendar year to sign them, even if they went back to college). Shortly before that deadline, Bird agreed to sign with the Celtics for a US $650,000 a year contract, making him at the time the highest-paid rookie in the history of the NBA. Shortly afterwards, the NBA draft eligibility rules were changed to prevent teams from drafting players before they were ready to sign. The rule is called the Bird Collegiate Rule.

http://en.wikipedia.org/wiki/Larry_Bird