College players who have finished their four-year college eligibility are automatically eligible for selection, while the underclassmen have to declare their eligibility and give up their remaining college eligibility. International players who are at least 23 years old are automatically eligible for selection, while the players younger than 22 have to declare their eligibility. Players who are not automatically eligible but have declared their eligibility are often called "early-entrants" or "early-entry candidates".