Everyone knows about the one-and-dones who went on to star in the NBA, but there are also the more unfortunate ones who are either struggling in the NBA or are out of the league altogether.
(Editor's Note: For Part 1 of Myron Medcalf's in-depth look at the NBA's minimum age requirement, click here.)
Omar Cook, St. John’s: Cook played just 17 games in the NBA after being drafted in the second round in 2001. Since then, he’s spent time in the D-League and has played for seven teams overseas.
Javaris Crittenton, Georgia Tech: Crittenton averaged just 5.3 points in 113 NBA games and couldn’t stay out of trouble off the court. He was suspended for the remainder of the 2010 season after he and teammate Gilbert Arenas drew guns on each other in the Washington Wizards' locker room. Crittenton is awaiting trial on murder charges after the shooting death of a 22-year-old Atlanta woman last year.
Eddie Griffin, Seton Hall: Griffin was the No. 7 overall pick in the 2001 NBA draft after averaging 17.8 points and 10.7 rebounds as a freshman at Seton Hall. But a poor work ethic and issues with alcohol kept Griffin from flourishing in the NBA. He died when his car struck a moving train in 2007. An autopsy discovered that his blood alcohol level at the time of the crash was more than three times the legal limit.
Donte Greene, Syracuse: The 28th overall pick in 2008 has averaged 6.1 points the past four seasons with the Sacramento Kings. Greene has a career field goal percentage of 40.6 percent -- and he’s made only 30.6 percent of his 3-point attempts.
Kosta Koufos, Ohio State: The 23rd overall pick in the 2008 draft has averaged 3.8 points and 3.1 rebounds in 182 games. His best season came in 2011-12, when he averaged career highs in points (5.5) and rebounds (5.4) for the Denver Nuggets.
Byron “B.J.” Mullens, Ohio State: The 24th overall pick in the 2009 draft hardly saw the court in two seasons with Oklahoma City. Mullens, though, appears to have found new life in Charlotte, where he averaged 9.3 points and 5.0 rebounds last season.
Jamal Sampson, Cal: Sampson was selected in the second round (47th overall pick) of the 2002 draft. He played in just 72 NBA games from 2002 to 2007 and averaged just two points and 3.4 rebounds. He has since spent time in the D-League and overseas.
Dajuan Wagner, Memphis: Wagner -- who scored 100 points during a single high school game -- averaged 13.4 points as a rookie in 2002-03 but was hampered with health issues from that point forward. He was hospitalized for ulcerative colitis the following season and eventually had to have his entire colon removed, essentially ending his NBA career.
Rodney White, Charlotte: White was regarded as the top freshman in the country when Detroit selected him with the ninth overall pick in 2001. He was traded to Denver after one season and averaged 7.7 points in 186 games. He since has played for 10 teams overseas.
Brandan Wright, North Carolina: The eighth overall pick in 2007, Wright has averaged just 5.9 points in four NBA seasons. He scored 6.9 points a game for the Dallas Mavericks in 2011-12.
*Note: Injuries have kept former Ohio State star Greg Oden from living up to expectations with the Portland Trailblazers, who selected him with the No. 1 overall pick in 2006. Oden has performed admirably when healthy, providing hope that he still has a chance to be an impact player in the NBA.
More: Jason King has a list of one-and-dones who became stars, like Carmelo Anthony and Chris Bosh.