While the success of NBA rookie of the year LeBron James may have encouraged more prep players to jump directly to the NBA, it has yet to convince many of the league's general managers that high school seniors are better NBA prospects than those who have polished their skills in college basketball.

Nine high school seniors are eligible for this year's draft, the youngest talent pool ever for an NBA draft. At least five prep players are likely to be chosen in the first round Thursday, including Dwight Howard from Southwest Atlanta Christian Academy, Shaun Livingston of Peoria (Ill.) Central High and Josh Smith of Oak Hill Academy in Virginia.

"It's a deep draft but a very young draft," said Wizards General Manager Ernie Grunfeld at a recent NBA pre-draft camp in Chicago. "It's probably not a draft that's going to produce a lot of impact players right away."

James, the No. 1 pick in last year's draft, averaged 20.9 points, 5.9 assists, 5.5 rebounds and more than 39 minutes a game last season and nearly took the Cleveland Cavaliers to the playoffs. NBA scouts doubt they will soon see a high school senior with the same combination of size, skill, athletic ability and maturity, and none of the prospects this year has done much to change their minds.

The 6-foot-11, 250-pound Howard is rated by most scouts as the top high school prospect. A versatile power forward who has wowed scouts with his dribbling and shooting skills, Howard has also impressed with his good grades, strong religious beliefs and affable demeanor (he does impersonations of characters from the Disney movie "Finding Nemo").

He is expected to be chosen by the Orlando Magic with the draft's first pick or by the Charlotte Bobcats at No. 2. Should the Magic take him, Howard would be the second high school player in the past three seasons to go No. 1. Three years ago, the Wizards selected Kwame Brown out of Georgia's Glynn Academy.

But even Howard may find himself on the bench next season, according to Portland Trail Blazers General Manager John Nash.

"What we're seeing is players with size and potential but you don't see the finished product," Nash said. "There are very few players in this draft that are ready to step in and play meaningful minutes in the NBA. . . . I don't know that Dwight Howard is capable of stepping in and playing right now."

Another who might struggle in his rookie season is Livingston, a 6-6 point guard favored for his height and passing skills but who, at 175 pounds, is considered too thin to withstand the pounding of an NBA season.

J.R. Smith of St. Benedict's Prep in Newark dazzled fans at the McDonald's High School All-American game this year by scoring on a whirling 360-degree dunk but scouts wonder whether he can dribble well enough for the NBA.

Point guard Sebastian Telfair, from Brooklyn's Lincoln High School, has been touted as a future NBA player since the eighth grade but, at 6 feet, 165 pounds, he is too short to defend NBA guards effectively, say some NBA executives. Several scouts have said that Telfair, the cousin of New York Knicks guard Stephon Marbury, has yet to prove he can consistently made three-point shots.

Predicting which of these players will develop into stars is up to the 30 NBA general managers and it has left them a little skittish.

For them, a younger talent pool is fraught with risks. Just a decade ago, they had four years in which to evaluate a player who came up through the college ranks. They get fewer opportunities to see high school players compete and rarely against other NBA prospects or top-level talent. Off the court, some teenage players have never been away from home for an extended period, so they must learn to take care of themselves and adapt to a completely new lifestyle. This too can hinder their development

Teams must also guess on how a teenager's body may develop. For instance, the 18-year-old Howard says doctors have told him he could grow to 7 feet.

"As the players have become so much younger, you're drafting sometimes a lot more on potential," said Grunfeld. "There are some very talented players in this year's draft, just like there normally are, but many of them you will have to wait on."

And many teams are willing to wait for fear that they might miss out on a future star. This year's class of high school seniors is so packed with promising young players that it has been compared to the class of 1979, which featured Isiah Thomas, Dominique Wilkins and James Worthy.

For this reason, there is no shortage of confidence among this year's potential high school draftees.

"There's not that many shooters that can make an impact on a team," said J.R. Smith. "That's what a lot of teams look for and that's what I know I can do."

Most of the prep players say they see themselves playing a lot in their first season. Some, however, realize they are a work in progress.

"I'll definitely need a strong supporting cast," said Livingston at a news conference in Chicago. "I'm going to need a lot of hands-on experience just because of my lack of experience and age.

"I'm going to step into a whole new world."

Forward Dwight Howard is one of several high school players likely to be selected in the first round Thursday. Sebastian Telfair, a cousin of Knicks guard Stephon Marbury, has talent but at just 6-0 and 165 pounds may have trouble defending NBA guards.