Here is a list of players that were just out of high school or under 19 when they were drafted. This list of players could prove that the NBA begun to draft players too early and waste a lottery pick. It started off fairly well with 1 or 2 players each year to 8 in 2004, the NBA decided to step in with the age minimum or 19 and 1 year out of high school regulation. I believed that this is a good move for the NBA as a whole.
(btw, it is possible that I may missed some players)
The First and Successful Group
Kevin Garnett~19~1995~Minnesota (very successful with the Timber Wolves)
Kobe Bryant~17~1996~Lakers (very successful with the Lakers)
Jermaine O'Neal~17~1996~Trail Blazers(didn’t have much playing time for 2.5 years with Portland, traded for only Dale Davis to the Indiana Pacers)
Tracy McGrady~18~1997~Raptors (finally played well in the 3rd year with the Toronto Raptors, only left and signed with the Orlando Magic and the Raptors got nothing in return)
These 4 players became very successful in the NBA, but only KG was an important contributor in the rookie year. And 2 of them left the team that drafted them with almost nothing.
The Second and very average Group
Al Harrington ~18~1998~Pacers (became a decent starter)
Korleone Young~19~1998~ Philly (played summer league for the 76ers, but never made another NBA roster)
Rashard Lewis~18~1998~Supersonics (bad rookie year, but became pretty good)
Jonathan Bender~18~1999~Pacers (forced into retirement due to chronic knee pain, yet to sign retirement papers)
Leon Smith~18~1999~Supersonics (signed by them, but only played one game)
Darius Miles~18~2000~Trail Blazers (ok player but injuries slow him down already, lost the entire 06/07 season)
DeShawn Stevenson~19~2000~Jazz (playing off the bench right now, and not expecting anything more from him)
This group isn’t doing very well in the NBA.
The Third and Drafted too high Group
Kwame Brown~19~2001~Capitals (didn’t worth a 1st overall pick, lets just say, he is still not very good)
Tyson Chandler~18~2001~Clippers (solid defensive player, but offensive game never develop
Eddy Curry~18~2001~Bulls (doing good in offense mainly due to his big body, slow defender and do not rebound)
DeSagana Diop~18~2001~Cavaliers (only used to play defense with his big body)
Tony Parker~19~2001~Spurs (good choice for a 28th overall pick)
This group all get to play and will continue to play but only Parker had became a major contributor for his team, but Parker had play professional b-ball since he was 14 in Europe. Tyson Chandler still has a lot of potential, could build off his defensive ability. With Brown, Chandler, Curry and Diop being the the 1st, 2nd, 4th and 8th pick, they were picked way too early.
The Fourth (old age Amare) Group
Amare Stoudemire~19~2002~Suns (won Rookie of the Year award)
He was over 19 when he was drafted and 20 within 1st month after the 03/04 season began.
The Fifth (LeBron and the others) Group
LeBron James~18~2003~Cavaliers (he has a NBA body out of high school, became very successful)
Darko Miličić~18~2003~Pistons (didn’t have a chance to play in Detroit and still hasn’t shown his potential)
James Lang~19~2003~Hornets (sidelined by back injuries, and didn't show the potential of being put on an "active roster)
Kendrick Perkins~18~2003~Celtics (still a bench player, even with the injury problem that the Celtics had this 06/07 season)
Again only 1 player lived up to potential and James was the fist player to have a major impact to his team in the rookie season since Kevin Garnett.
The Sixth and Getting Out of Control Group
Dwight Howard~18~2004~Magic (this guy is huge, good defensively but lack offensive moves)
Al Jefferson~19~2004~Celtics (played very well this past season [06/07])
Shaun Livingston~18~2004~Clippers (may be out 8-12 months after suffering a severe knee injury)
Josh Smith~18~2004~Hawks (very good jumping abilities, also very inconsistent, has lots of potential, but still need time to develop)
J.R. Smith~18~2004~Hornets (played for 3 teams in 3 seasons, playing well with the Nuggets but again prove my point of a wasted pick for the team that draft the high school player)
Robert Swift~18~2004~Supersonics (out for this season, torn ACL)
Sebastian Telfair~19~2004~Trail Blazers (not a bad player when he plays well but getting into law trouble and the Celtics don’t plan on keeping him around)
Dorell Wright~18~2004~Heat (played well at the beginning of the 06/07 season but quickly back to the bench and lost playing time)
Ridiculous number of high school player drafted in 2004, and most of them aren’t that good and should have went to college and play in NCAA for at least a year. I believed that this draft triggered the age minimum regulation.
The Seventh and Final High School Players Group
Andrew Bynum~18~2005~Lakers (show promising signs early on 06/07 season, but faded away by the end of the season)
Monta Ellis~19~2005~Warriors (played very well in his 2nd year, but wasted the 1st season, a solid pick in the second round)
Gerald Green~19~2005~Celtics (won the slam dunk title but don’t get much playing time with the Celtics)
Martell Webster~19~2005~Trail Blazers (had a solid rookie year, but with the addition of Brandon Roy, Webster’s development halted in his second season)
This group has potential but again need a couple more years to develop.
9 all stars (Kevin Garnett, Kobe Bryant, Jermaine O’Neal, Tracy McGrady, Rashard Lewis, Tony Parker, Amare Stoudamire, LeBron James, and Dwight Howard)
2 slam dunk champs (Kobe Bryant and Gerald Green)
3 don’t get past first year (Korleone Young, Leon Smith and James Lang)
4 out of NBA already (Korleone Young, Leon Smith, Jonathan Bender and James Lang)
4 with serious injury that had lost an entire season within 4 years (Jonathan Bender, Darius Miles, Robert Swift and Shawn Livingston)
Only 3 had impact on team in rookie year (Kevin Garnett, LeBron James and Dwight Howard)
16 played for only one team (12 of them were drafted after the 2002 season, so only 4 of them stay in original team for more than 4 years at this moment)
Most of these guys do not develop in time (within 3 years rookie contract) for the team that drafted them, so why do it, the NBA had the right idea of stopping teams from drafting players that are under 19 and within 1 year out of high school.