<Li> Any player who is not an "international player", as defined in the CBA, must be at least one year removed from the graduation of his high school class . </Li> <P> The "one year out of high school" requirement is in addition to the age requirement . For example, although O.J. Mayo turned 19 in November 2006, six months before his high school graduation, he was not eligible until the 2008 draft, a year after his high school class graduated . Stern stated the rules were business - related and not a "social program", citing the need to see players perform against higher competition before they are evaluated for valuable draft picks . The rule effectively mandated that players spend at least one year in college . High school players who would otherwise have jumped directly into the NBA were instead playing in college for the required year before leaving and entering the draft--a phenomenon known as one and done . Some colleges have embraced this rule to their advantage, notably the University of Kentucky, among others . Many of their players have played the one mandatory year, leaving after their freshman season to enter the draft . The NBA G League (formerly Development League) is one alternative to college . Players can earn five - figure salaries, but the level of competition is possibly lower than in the Division I level in college . Some players, most notably Brandon Jennings, have also played overseas in lieu of college . However, in recent years, other players like Satnam Singh, Thon Maker, and Matur Maker have looked to enter the NBA draft while still being high schoolers by exploiting a loophole where they enter the draft as high school postgraduates . </P> <P> Players whose 19th birthday falls during or before the calendar year of the draft, or at least one year removed from the graduation of their high school class, and who do not meet the criteria for "international" players are automatically eligible if they meet any of the following criteria: </P> <Ul> <Li> They have completed four years of their college eligibility . </Li> <Li> If they graduated from high school in the U.S., but did not enroll in a U.S. college or university, four years have passed since their high school class graduated . </Li> <Li> They have signed a contract with a professional basketball team outside the NBA, anywhere in the world, and have played under that contract . They also must be released from their contract before they can leave college to go to the NBA </Li> </Ul>

At what age can you enter the nba
find me the text answering this question