Calling it quits is difficult for any professional athlete. Just ask Brett Favre, who has yet to make a decision (surprise, surprise!) about whether or not he will play in the NFL again next season. Often times, the will to play overpowers the skills to play in older athletes and forces them to hang on for one...more...year in order to try and leave their sport at the top of their game.

Unfortunately, the recent retirement of Allen Iverson (wait, are we really ready to call it that yet?) reinforces a problem that many NBA players have faced at the end of their career. A.I. has not only had to deal with his diminished skills on the court--he's also allegedly had to battle his demons off of it. It's been enough to essentially force him out of the game that he's loved so much for so many years. But he's not the first player to face this fate. From contract negotiations gone bad to substance problems to devastating injuries, there are plenty of former NBA stars that have been forced to cut their careers short and leave the game under less-than-ideal circumstances. StreetLevel rounded up ten of the most heart-breaking scenarios...

Latrell Sprewell
A four-time NBA All-Star who helped lead the New York Knicks to 1999 NBA Finals, Sprewell's career came to a screeching halt in October 2004 when he turned down a three-year, $21 million contract offer from the Minnesota Timberwolves by declaring, "I have a family to feed." Though some other teams expressed interest in signing him in 2005, he refused to sign for the veteran's minimum and never played in the league again. Ironically, since leaving the NBA, Sprewell has been sued by his long-time girlfriend to the tune of $200 million, had his yacht repossessed, and seen his Milwaukee mansion go into foreclosure. Who's money-hungry now?


Dennis Rodman
After a successful career with the Detroit Pistons, San Antonio Spurs, and Chicago Bulls, Rodman probably should have put away the hair dye and called it a career. Instead, he spent 23 games with the Los Angeles Lakers during the 1998-99 season before being released and then signed on with the Dallas Mavericks for the 1999-2000 season. But he only played 12 games, got ejected from two of them and quipped, "David Stern and Rod Thorn, they need to get their ass kicked," during his time with the team. Way to take the high road on your way out!


Stephon Marbury
Like Sprewell, Marbury actually turned down a contract for the veteran's minimum from the Boston Celtics after the 2008-2009 season. At the time, he said he wanted to take a year off and focus on his business opportunities. He then proceeded to spend the next year eating Vasoline and playing pro ball in China. Starbury's star may have finally burned out.


Allan Houston
Knicks fans know the story: Houston signed a maximum contract with them team in 2001. But by 2003, he injured his knee and never made a serious impact on anything but the Knicks salary cap ever again, costing them over $20 million a year for the duration of his contract. He tried to launch comebacks in 2004, 2005, 2007, and 2008 but finally hung up his sneaks for good in '08. He even has a rule named after him. How flattering embarrassing. Knicks fans still cringe when hearing his name.


Anfernee "Penny" Hardaway
Following the departure of Shaquille O'Neal after the 1995-96 season, Penny was the savior of the Orlando Magic franchise. At first, he lived up to the hype, too, but a devastating left knee injury during the 1997-98 season started a downward spiral that lasted nearly ten years. Over the next decade, Penny played for the Phoenix Suns, New York Knicks and Miami Heat-and suffered a series of catastrophic knee injuries that eventually diminished his skills and forced the Heat to cut him in 2007. "I don't like the way it ended," he said shortly after being forced out. "I have some good basketball left in me." Guess we'll never know.


Earvin "Magic" Johnson
Tragic? Unbelievable? Heart-breaking? One of the best players to ever play in the NBA announced that he had been diagnosed with HIV just before the 1991-92 season. He did play sparingly in the 1992 Summer Olympics as part of the Dream Team and even made a comeback attempt prior to the 1992-93 season and during the 1994-95 season. But, truth be told? The magic in Magic was gone.


Shawn Kemp
The Reign Man knew how to throw down a nasty dunk. But after a successful eight-year career with the Seattle SuperSonics, Kemp also apparently knew how to throw down in the kitchen, as he showed up to training camp with the Cleveland Cavaliers prior to the 1997-98 season battling weight problems. His issues continued as he struggled with cocaine and alcohol abuse as a member of the Portland Trail Blazers in the early 2000s before fizzling out as a member of the Orlando Magic in 2002-03. The only opportunity he got after that was a three-game stint in Rome in 2008. Reign over.


Vin Baker
Once regarded as "America's Best Kept Secret" by Sports Illustrated during his college days at the University of Hartford, Baker played for almost a decade before announcing a secret of his own during his 2002-2004 stint with the Boston Celtics: He was an alcoholic. Though he got treatment and played with the New York Knicks, Houston Rockets and Los Angeles Clippers after revealing it, his last call came in 2006 when the Minnesota Timberwolves cut him--and he never played again.


Robert "Tractor" Traylor
Though he managed to avoid any jail time for laundering money for his drug-dealing cousin in 2007, Tractor Traylor's struggles with obesity and a heart problem forced him out of the league in 2005 after stints with the Milwaukee Bucks, Cleveland Cavaliers and New Orleans Hornets. His biggest claim to fame is also being selected by the Dallas Mavericks in the 1998 NBA Draft before getting traded immediately for future NBA All-Star Dirk Nowitzki. What a legacy.


Michael Jordan
It's no surprise MJ did a lot of great things during his storied NBA career. But he didn't do everything great. Specifically, His Airness's swan songs have been about as forgettable as Jay-Z's "retirement" plans. In 1993, he retired to play baseball--and came back. In 1999, he retired again--and came back. Finally, in 2003, Jordan retired for good after a two-year comeback with the Washington Wizards. But, by our count, that still leaves him shooting about 30 percent from the field when it comes to retirement. Come on, Mike. If you say you're done, just do it!


These are just a few of the most disappointing retirements from the NBA. Got a better one? Leave a comment below and tell us about it.