The NBA has a steep learning curve, which is why the annual debate over rookie of the year rarely involves more than two or three players. Most successful players build their games slowly and steadily, but there are always the chosen few who manage to break out in their second year by consolidating their skill sets quickly, playing bulk minutes, and moving from promising to impact player in the span of just a few months.

Miami’s Dwayne Wade was the best example of this phenomenon last year. After a promising rookie season in which he averaged just over 16 points in 35 minutes a game,Wade managed to steal some of Shaquille O’Neal’s spotlight last season by averaging 24.1 points and hoisting the Heat from mid-level playoff also-rans to championship contenders.

Looking at the draft class of 2005, three inside players stand the best chance of having breakout sophomore seasons: Boston’s Al Jefferson, New Jersey’s Nenad Krstic, and Golden State’s Andris Biedrins. If they do, it would mark an interesting change in NBA tendencies. The success of players like Suns forward Amare Stoudemire is an exception; young big men are usually regarded as projects. Most face a rougher road than their perimeter counterparts, and it’s not hard to see why.

Perimeter players face comparably sized competition throughout their teenage years. But, the super sizing of a nation notwithstanding, the opportunity for a 6-foot-10-inch player to battle against kids his own size is limited. Most young paint players succeed mostly by being taller than their competitors; skills like agility, footwork, and recognizing spin on the pending rebounds aren’t so essential for success at the earlier levels.

It is only upon arrival in the NBA that many young power forwards and centers face competitors who are as big if not bigger, not to mention quicker and more fundamentally sound. Moreover, the intense level of contact that youngsters find in the NBA can quickly take a toll on a body that isn’t physically mature. Even Indiana’s Jermaine O’Neal and Chicago’s Tyson Chandler, successful NBA pivotmen who were drafted as teenagers, took four years to hone their games.

That’s what makes the current emergence of young big men so surprising. Jefferson, Krstic, and Biedrins have cleared the usual hurdles in a remarkably short period of time, as has Orlando’s Dwight Howard (but the no. 1 overall pick can’t be a breakout candidate). They are better bets than perimeter sophomores such as Chicago’s Luol Deng, Philadelphia’s Andre Iguodala, and Atlanta’s Josh Smith and Josh Childress. These guys all run the floor well and throw down highlight dunks, but unresolved range issues are likely to hold all four back, if their performances in the preseason are any indication. Smith, for instance, bricked his way to a 1-for-10 shooting clip on Monday night.

By contrast, Biedrins was busy collecting 12 rebounds in 25 minutes against Utah on Monday. Biedrins, a 19-year-old center from Latvia, may be one of the bigger surprises of the season. He fell to the Warriors late in the lottery last year, a likely reflection of the skepticism surrounding European big men following the failures of Nikoloz Tskitishvili, Darko Milicic, and – as Knick fans painfully know – Frederic Weis.

But after spending the first three months of last season at the end of the bench, Biedrins began paying dividends for the Warriors, shooting 62.7% from the field in March and finishing the season by averaging a double double (11.4 pts/12.3 boards) per 40 minutes. The Warriors finished 16-7 after he moved into the rotation. This year, with only Adonal Foyle ahead of him in the pivot, Biedrins should get much more burn. Duplicating his numbers from last season would be an accomplishment, but with a good touch on a midrange jumper to go with other natural gifts, he figures to add to the impressive totals.

If Biedrins doesn’t alter the perception of European big men, then the Nets’ Nenad Krstic will. Like Biedrins, Krstic began slowly as a 21-year-old rookie last season, seeing only garbage-time minutes through the first couple months of the season. But by late December, he had won a spot in Lawrence Frank’s rotation. By season’s end, Krstic was posting 40-minute averages of 15.2 points and 8.2 rebounds in a starting role.

Those numbers would have been higher had Krstic not fallen prey to one of the other common pitfalls of young NBA inside players: foul trouble. He’s almost manic in his pursuit of rebounds. With a better understanding of the contact he can and can’t get away with, Krstic will spend more time on the court and score on putbacks after misses by Vince Carter, Richard Jefferson, and Jason Kidd.

Improved competition in the Eastern Conference is likely to swat the Celtics from the playoff picture, but it probably won’t be Al Jefferson’s fault. Jefferson, who was drafted out of a small high school in Mississippi last year, wowed observers with his fluid footwork, and solid fundamentals. The 6-foot-10-inch, 265-pound power forward, who was 19 at the start of his rookie campaign, began the season in Doc Rivers’s rotation and surprised nearly everyone by averaging 18.1 points and 11.9 boards per 40 minutes. Jefferson’s playing time diminished after Antoine Walker was re-acquired for a playoff push, but he’ll have no one ahead of him on the depth chart this season. With his superb post moves, he should should join the ranks of the league’s top power forwards.

The emergence of this new class of young big men may alter the way the league projects talent. Biedrins and Jefferson undoubtedly fell a few spots on draft night because league execs were wary of taking a pick that would need time to mature. The accelerated timetable these three big men have followed should spark a renewed willingness on the part of scouts and executives to take chances on bigs lacking substantial NCAA experience. With the age limit in place, it probably means an even bigger stampede to the one-and-done approach to college ball, and some teenagers may opt to spend a year in the NBA’s newly expanded Development League.

The bigger impact will come on young post players like the Knicks’ David Lee and Channing Frye and the Lakers’ Andrew Bynum. They will be expected to develop very fast, even though the NBA’s learning curve is no less steep. It’s just an extraordinary few who have figured out how to master it quickly.

mjohnson@nysun.com