Rules of the game

The NBA’s shifting rules governing the eligibility of high school players:

Before 1971 -- Players had to be four years removed from their high school graduating class before entering the NBA draft.

1971 -- The Seattle SuperSonics challenged the rule by signing Spencer Haywood after he had spent two years in college and a year in the ABA. Haywood argued that he was a hardship case and the Supreme Court agreed, saying the NBA was in violation of the Sherman Antitrust Act, and overturned the league’s rule. The league then adopted a “hardship rule.”

1976 -- The league dropped the hardship limitation, and many players, such as Magic Johnson and Isiah Thomas, entered the draft before completing their eligibility. Kevin Garnett, Kobe Bryant and others entered NBA out of high school.

2005 -- The league adopted its current rule, saying a player must turn 19 the same calendar year as the draft, and be one year removed from his high school graduating class. This rule took effect for the 2006 draft.

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Sources: Times research, NBA.com