Brett Favre is hardly the first athlete to second-guess his retirement.

While news surround the upcoming NFL season is focused on if the quarterback will return to the Green Bay Packers, several other notable athletes have taken a break from competition only to return.

Some athletes came back in their old form, others were better than they were before, and others retired and un-retired several times.

From Lance Armstrong to Michael Jordan to Sugar Ray Leonard, take a look at a few of the more notable comebacks by athletes:

Lance Armstrong

After taking time off while fighting testicular cancer, Lance Armstrong returned to professional cycling in 1997.

He went on to win his first Tour de France title in 1999, and then won six more through 2005.

He was named The Associated Press Male Athlete of the Year in 2002, 2003, 2004 and 2005.

George Foreman

In 1977, boxer George Foreman fell ill in his dressing room after a fight and believed that he had a near-death experience.

The incident affected Foreman and he became a born-again Christian. For the next 10 years, Foreman stopped fighting and became an ordained minister of a Texas church.

Then, in 1987, Foreman decided to return to boxing at the age of 38. He fought several mediocre opponents before a matchup with Evander Holyfield in 1991. Foreman lost the fight, but he lasted all 12 rounds against the heavyweight champion.

The loss didn't stop Foreman's comeback, and in 1994, he regained the heavyweight title. Facing Michael Moorer in a title bout in Las Vegas, Foreman trailed Moorer for most of the fight before knocking him out in the 10th round to claim the title.

Michael Jordan

Following the death of his father, an emotionally drained Jordan announced his retirement from the NBA in October 1993.

The basketball legend was seeking new challenges, and he attempted to fulfill a dream by turning his efforts to baseball and making it to the Major League. But when his MLB hopes dimmed, Jordan turned his focus back to basketball.

In March 1995, Jordan came out of retirement by announcing, "I'm back." Wearing the No. 45 in an attempt to leave No. 23 behind, Jordan played in 17 regular season games in the 1994-95 season and averaged 26.9 points. His average included a 55-point outing against the New York Knicks.

After the Bulls were eliminated in the playoffs, Jordan set his sights on winning another championship the following season. Wearing the No. 23 again, Jordan led the league with 30.4 points per game as the Bulls earned 72 regular-season victories. The team capped off the year with the NBA championship. His individual efforts earned Jordan the MVP awards for the regular season, the finals and the All-Star game.

The Bulls went on to win two more NBA titles to capture another three-peat.

Mario Lemieux

NHL star Mario Lemieux made successful returns from cancer and retirement during his Hall of Fame career.

In 1993, Lemieux announced he was suffering from Hodgkin's lymphoma. He missed two months of the season before coming back to win the league's overall scoring title.

He retired in 1997, and spent most of the late nineties focusing front-office duties with the Penguins.

But in 2000, Lemieux turned his focus back to the ice. He came of out retirement to finish with the highest points-per-game average among players that season. He was also a finalist for Hart Memorial Trophy en route to helping the Penguins advance to the Eastern Conference finals.

Sugar Ray Leonard

After suffering a detached retina in his left eye, Sugar Ray Leonard retired from boxing in 1982.

However, his time off didn't last long. In 1983 he announced he would come back for a series of fights.

But in February 1984, Leonard announced his retirement again after a bout with Kevin Howard, claiming he just didn't have what it takes anymore.

Then, in 1986, Leonard announced another return to the ring -- this time for one fight against Marvin Hagler. The bout was held in April 1986, in Las Vegas, where Leonard won by a split decision.

Soon after, Leonard announced his retirement again before putting together another comeback in 1988.