From
http://en.wikipedia.org/w...bility_for_the_NBA_Draft
"Early entry" player
Players who are not automatically eligible, but wish to be drafted, must declare their eligibility no later than 60 days before the draft. After this date, "early entry" players may attend NBA pre-draft camps and individual team workouts to show off their skills and obtain feedback regarding their draft positions. A player may withdraw his name from consideration from the draft at any time before the final declaration date, which is 10 days before the draft. Note, however, that effective with the 2010 draft, college players must withdraw no later than May 8 to retain their college eligibility. A player who declares for the draft will lose his college eligibility, even if he is not drafted, if any of the following is true:
* The player signs with an agent.
* The player has declared for and withdrawn from a previous draft. Although the NBA collective bargaining agreement allows a player to withdraw twice,the NCAA only allows a player to enter the draft once without losing eligibility.
<sup id="cite_ref-NCAA_withdrawal_13-1" class="reference">
<span></span><span></span>