It's an inevitable fact that comes with the passage of time. Each season, the younger players in the NBA typically improve and enhance their respective skills, while the league's seasoned veterans usually take a step back as they rapidly approach the end of their careers.
There are a number of factors that cause those in the latter group to begin their slow decline. Some are squeezed out of starting roles, others are burdened by the after effects of injuries and others are simply unable to maintain the same level of play that they did five or 10 years ago.
So, as we look ahead to the 2012-13 campaign, here's a look at five stars who are headed for a major regression next season.
After 15 Hall of Fame-caliber seasons, the effects of playing more than 1,100 NBA games are finally taking a toll on Spurs forward Tim Duncan. And as much as it seems as though he (and San Antonio) will perpetually remain on top, the clock on their respective reigns will strike midnight soon enough.
Last year, Duncan averaged a career-low 28.2 minutes per game and failed to average a double-double for the second season in a row. With Kawhi Leonard projected to be the "face of the Spurs" going forward, expect Duncan to play more of a complementary role in 2011-12.
Even so, the 36-year-old Duncan is still one of the best big men in the game, and his fundamentally sound play is one of the reasons why no one ever wants to face the Spurs in the playoffs.
In 2011-12, Pau Gasol enjoyed his third consecutive season in which he averaged a double-double. That streak will likely come to an end this year following the Lakers' addition of Dwight Howard earlier this offseason.
Even though Gasol will be one of the focal points of LA's new Princeton offense, the 7'0" forward/center is now no better than the Lakers' No. 3 option behind Howard and Kobe Bryant. Gasol will get plenty of opportunities on pick-and-rolls in the high post, but he won't be called on to do much of the dirty work in the paint.
Gasol's regression next season won't be because of a declining skill set: At the 2012 Olympics, Gasol averaged 19.1 points and 7.6 rebounds per game as he led Spain to a silver medal.
David Lee had a stellar 2011-12 season for the Golden State Warriors (20.1 PPG, 9.6 RPG), and wouldn't appear to be a candidate for a regression next year.
However, with all due respect to Andris Biedrins, Lee has never had the pleasure of playing alongside a top-flight center. And if Warriors big man Andrew Bogut is fully healed from offseason ankle surgery, expect Lee's numbers to take a dip going forward.
For the past two years, Lee has had the lion's share of the low-post touches for Golden State because there were few others who could take them away from him. Next to Bogut (who works almost exclusively in the paint), Lee will have to defer somewhat, and his scoring and rebounding averages are sure to be affected.
Twelve years ago, Vince Carter took the NBA Slam Dunk Contest to heights that the competition has yet to return to more than a decade later. Now, he's regressed to the point where he's airballing layups.
The Dallas Mavericks are well aware that they can no longer count on Carter as a secondary option, so the team went out and signed combo guard O.J. Mayo earlier this summer. Carter's scoring and rebounding averages have declined steadily each of the past five seasons, and they don't figure to improve with him coming off of the bench next year.
To his credit, Carter realizes that he isn't the same player who jumped over Frederic Weis at the 2000 Olympics, and he plans to diversify his game going forward.
If Dwyane Wade's offseason knee surgery doesn't help him regain the explosion that he once had, then we may be seeing the beginning of the end of an illustrious run.
Wade averaged the fewest minutes of his career in 2011-12 (33.2 MPG), and his scoring average of 22.1 PPG was his lowest since his rookie year. While it was clear that Wade and the rest of his teammates voluntarily deferred to LeBron James last season, the 30-year-old Marquette product gladly assumed the No. 2 role as he was noticeably hampered by his ailing left knee.
Wade just recently started working out again on the basketball court, so even if he is ready for opening night, it's extremely unlikely that he will immediately regain his dominant, All-NBA form next season.