Last Friday, we took a look at five lottery teams on the rise that could make the playoffs next season. As those teams improve, inevitably some of the teams currently in the playoffs must go the opposite direction. Instead of looking just at teams which could slip out of the postseason picture, we've expanded our list to look at the playoff teams in order of likelihood of having their record drop off during the 2011-12 season.
1. Atlanta Hawks
Why they'll slip: While the Hawks won 44 games, they were outscored on the season, and point differential is a better predictor of future record than wins and losses are.
Why they'll stay strong: Al Horford's successful run as a power forward in the postseason against the Orlando Magic may be the precursor to Horford moving to the position full-time.
As good as Atlanta has looked in the current series with Orlando, there are worrisome signs ahead. Besides the Hawks' poor point differential--a product of repeated blowout losses, often at home--they went just 12-17 after the All-Star break. Making matters worse, Atlanta's high payroll and Jamal Crawford's impending free agency could force the Hawks to deal starting forward Josh Smith for cap relief. Atlanta will need significant improvement in other areas to top .500 again. The Hawks will have to do it without a first-round pick, having traded theirs to Washington with rookie Jordan Crawford to add Kirk Hinrich at the trade deadline.
2. San Antonio Spurs
Why they'll slip: For one, the Spurs have more room to fall than almost anyone else. On average, teams that win at least 60 games drop by 6.2 games the following season.
Why they'll stay strong: San Antonio is likely to get more production from rookie center Tiago Splitter after he's had a year to adjust to the NBA and the team's system, not unlike how Richard Jefferson was more effective this year.
The Spurs might care less about their regular-season win total than any team east of the Staples Center, which made it all the more remarkable that they held the league's best record virtually the entire season and earned the Western Conference's top seed. Gregg Popovich has skillfully managed the minutes of his veteran stars, but the Spurs also benefited from some good fortune that their big three of Tim Duncan, Manu Ginobili and Tony Parker combined to miss just 12 games total. Parker alone missed 26 in 2009-10. With normal health and a few bad breaks, San Antonio is likely to win somewhere closer to 55 games next season than 61.
3. New Orleans Hornets
Why they'll slip: No team in the league is more dependent on a single player than the Hornets are on Chris Paul. If he misses time, New Orleans could slip quickly.
Why they'll stay strong: In his first year as head coach, Monty Williams produced a defensive turnaround. As Williams establishes his system, the Hornets may get even better on defense.
Paul has been dazzling in the playoffs against the Los Angeles Lakers, but it's more difficult for him to carry such a heavy load over the long regular season after arthroscopic knee surgery in 2010. Paul has long leaned heavily on David West, who tore his ACL in April and might not be all the way back from the injury at any point during the upcoming season. Carl Landry, who has filled in effectively for West, is an unrestricted free agent and might not be back, further compromising New Orleans' depth. If West isn't ready for the start of the season, Paul might have to score 30 points a night to keep the Hornets competitive.
4. Boston Celtics
Why they'll slip: As impressive as their performance deep into their careers has been, Ray Allen, Kevin Garnett and Paul Pierce can't continue to hold off age forever.
Why they'll stay strong: The same thing could have been written this time a year ago and the Celtics ended up winning six more games than they did in 2009-10.
Boston has made a habit of starting the regular season strong and slumping to the finish line. That might be exacerbated as the Celtics' trio of stars advances deeper into their 30s. In Danny Ainge's master plan, the acquisition of Jeff Green at the trade deadline would provide a needed infusion of youth. However, Green has struggled since arriving in Boston, leaving the Celtics more dependent on their starters than ever. That will make things difficult if Doc Rivers feels he needs to give his veterans more rest to keep them fresh for the postseason.
5. Dallas Mavericks
Why they'll slip: While everyone worries about Boston's age, the Mavericks were actually the league's oldest team when weighted for minutes played with an effective age of 31.4 years old. (The L.A. Lakers, at 30.9, were next.)
Why they'll stay strong: Dallas has won 50-plus games for 11 years running, so it's difficult to see the Mavericks slipping too badly.
On paper, Dallas is one of the most likely candidates to regress next season. Like the Hawks, the Mavericks outperformed their point differential, which was more consistent with a 52-win team than the 57 Dallas actually won. However, this is nothing new for the Mavericks, who have overachieved relative to their differential on a regular basis since Jason Terry joined Dirk Nowitzki to form a potent crunch-time duo. Instead, the biggest threat to Dallas is Father Time. Starting point guard Jason Kidd is 38 and slipped noticeably this season, and there isn't a replacement for Kidd on the current roster. Fellow starters Nowitzki (33 in June) and Shawn Marion (33 in May) and key reserves Terry (34 by training camp) and Peja Stojakovic (34 in June) are all at an age where they can be expected to decline.
A version of this story originally appeared on ESPN Insider .
Kevin Pelton is an author of Basketball Prospectus.
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