Those who follow sports as closely as I do are probably already aware of the Allen Iverson saga that took place over the past couple weeks. The one-time National Basketball Association (NBA) Most Valuable Player and ten-time NBA All-Star set a new world record, and it is not the number of people watching his press conference on YouTube because it is funny to watch grown men cry.

Iverson's retirement and subsequent unretirement from a professional sport must have been the fastest ever of a little complex I like to call the Brett Favre Syndrome.

On November 25, Allen Iverson claimed he was officially retiring from professional basketball. Less than a week later, Iverson announced he was returning to the game, signing a contract with the Philadelphia 76ers, the team that drafted Iverson first overall in the 1996 draft.

What is it about professional athletes that make them so susceptible to the act of unretiring? Often there are no financial motivations, as the athletes have made more than enough money to afford a long life of luxury.

But it seems to happen all the time! It goes far beyond Brett Favre and Allen Iverson. The syndrome made me look through the history of athletes who have decided it was time to leave the game/retire, only to decide later that it was time to make a comeback/unretire.

Probably the most notable athlete to do this was Michael Jordan, considered by many to be the greatest athlete of all time. Jordan retired from professional basketball in 1993, citing a loss of desire to play the game. Then he pursued a career as baseball player, only to retire from that due to a lack of talent. By 1995, Jordan unretired and was back playing basketball professionally with his Chicago Bulls, spurred on by his leading the Looney Tunes to victory over the Monstars in a basketball game for the fate of the planet (oh wait, that was the plot of Space Jam...).

Unretirement proved to be a smart move for Jordan, who won three more NBA championships before retiring again in 1999. Jordan claimed that he was 99.9 percent sure that he would never play again, which of course led to his inevitable second unretirement in 2001. Jordan finally retired for good (we hope) in 2003, after an uneventful two seasons with the Washington Wizards.

In baseball, the undisputed king of unretiring would be Roger Clemens, who retired after the 2003 season, unretired before the start of the 2004 season, retired after the 2005 season, unretired in the middle of the 2006 season and unretired again in the middle of the 2007 season before finally retiring for good. Clemens posted some fantastic numbers during some of those seasons, including a 2005 season that was maybe the best of his career, leaving many to wonder how someone could throw the ball so well at such an advanced age (Clemens turned 40 in 2002). That mystery was solved when his use of performance enhancing drugs became known. "Anabolic Steroids: side effects may include liver problems, acne and a burning desire to be unretired multiple times."

One name that comes up frequently when discussing unretired athletes is hockey player Mario Lemieux, who retired in 1997, unretired in 2000 and retired again in 2006. Lemieux is unquestionably one of the greatest hockey players of all time, so it is understandable that he gets thrown into the conversation, but I think this is unfair. Lemieux's first retirement came due to a battle with cancer, and if you are retiring and unretiring because of a bout with any deadly disease, you deserve praise, not blame.

Ultimately, when it comes to unretirement, no other athletes can match the antics of professional boxers such as George Foreman. Foreman had a semi-retirement in 1975 before unretiring in 1976. However, a fight in 1977 against boxer Jimmy Young led to a religious experience, in which Foreman claimed that Young "knocked the devil out of him." Foreman spent this retirement as an ordained minister at a church in Houston, Texas. Ten years later, Foreman unretired, again, holding his own in the ring once again, and managed to fight until 1996, all while also selling lean, mean, grilling machines. Of course, this is the man who lost so many brain cells fighting that he named his five sons George Jr., George III, George IV, George V and George VI, so we can probably assume he forget about any previous retirements or unretirements.