NBA rookies are supposed to struggle their first year in the league. The learning curve is steep, and new players are often overwhelmed with both the physical and mental hurdles of an 82-game regular season. Even future stars are often thought to go through serious adversity as they grapple with the pro game over the course of their first year.
However, upon closer examination, the assertion that future NBA stars have significant difficulties on the court as rookies is overblown. An excellent indication of how good a player can eventually become is by looking at how well he performs in his first season.
John Hollinger's Player Efficiency Rating (PER) is a catch-all statistic that is valued for both its simplicity and its bluntness. While many experts chafe at using a single statistic to define a player's value, the effectiveness of PER as an analytic tool is hard to deny. Examining a highly touted rookie's PER is a great way to soberly analyze their chances of stardom.
Since the 2002 Draft there have been 20 players picked that have gone on to make at least two All-Star games. According to basketball-reference.com, only one of these players posted a PER below 13 in his rookie season — Deron Williams.
What is more, of these twenty stars selected since 2002, only Williams, Rajon Rondo and Al Horford had a PER below 15 their rookie year.
A PER of 15.00 is considered average. So using PER as our judge, since 2002 most rookies who went on to great success were actually above average players right away. And while a 13.0 PER is slightly below average, it cannot be considered bad. At worst it seems future great players start their careers by being adequate.
These rookie PER numbers are a bigger deal than some might expect. While a PER of over 15 is no guarantee for future stardom, it does seem like a general prerequisite. This is especially true for power forwards and centers - historically very few big men have gone on to achieve great success without posting a PER of at least 15 right out of the gate.
Players like Horford are the exception, and in his case at least he was very close to the number. This casts a cloud of doubt on highly touted young bigs like DeMarcus Cousins (rookie season PER: 14.6), Derrick Favors (13.9), Omer Asik (11.8), Nikola Pekovic (11.2), Derrick Willaims (12.9), Enes Kanter (14.5) and Tristan Thompson (13.3.)
Having a PER of 15 right away does not historically seem as vital a prerequisite for guards and swingmen, but a PER below 13 should always raise a red flag.
Most players who end up having superior careers post at least a 13.0 PER as rookies. If they can't hit that number it makes it unlikely as to whether that player can ever turn into a legitimate star. Teams should be skeptical of hyped young players like Jrue Holiday ( rookie PER: 12.3), Evan Turner (10.8), Gordon Hayward (10.7) and Brandon Knight (11.7.) None seem likely to fulfill high expectations, and all are candidates to become overpaid once their rookie contracts expire.
As you would expect, there are exceptions to these PER requirements, especially among point guards (Steve Nash and Tony Parker are examples of point guards who posted a low rookie PER), but it should be understood that the vast majority of great players are good from the very beginning.
All-Stars get progressively better as their careers move along, but they start by being immediately capable pros. Their initial struggles are somewhat minor compared to the growing pains of many of their less talented rookie counterparts.
Projecting what rookies will actually fulfill their potential is vitally important to managing a NBA roster. Many young players are considered "untradeable" their first few years in the league because their upside is so high.
The reality is most young players do not deserve to be held in such high regard. A rookie's PER shows if a player has a chance to be exceptional. It allows teams not to invest too much hope on a highly touted player that will likely never live up to expectations. It is a number everybody should keep an eye on with this year's rookie class.