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George Foreman came out of retirement in 1987 and earned a world title shot against Evander Holyfield.
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Michael Jordan twice retired from basketball, returning for a final time with the Washington Wizards in 2001.
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Imran Khan was hauled out of retirement in 1992 and led Pakistan to the World Cup trophy at 39.
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Both Pele (r) and George Best came out of retirement to play in the USA.
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Best had twice retired after fallouts at Manchester United in 1972 and 1973 while only 27.
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Floyd Mayweather (r) has called it a day three times, his most famous comeback being after his 2008 retirement after beating Ricky Hatton.
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Disgraced cyclist Lance Armstrong returned to the Tour de France in 2008 after three years in retirement.
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In 2009 Michael Schumacher returned to Ferrari after Felipe Massa's tragic crash.
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Jonah Lomu took to the field for Marseille Vitrolles in 2009, two years after hanging up his legendary boots.
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Two years after retiring, Kim Clijsters won the 2009 US Open in a hugely successful return to the court.
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A neck injury ended Steve Thompson's career in 2007 but he returned later that year and went on to play in England's 2011 World Cup campaign.
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Paul Scholes helped ease Manchester United's injury crisis by coming out of retirement for half a season, helping them lift the 2012/13 EPL title.
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Since coming out of retirement in 2013, Martina Hingis (r) has formed a dominant doubles pairing with Sania Mirza.
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Pakistan cricketer Shahid Afridi has retired numerous times during his career, the latest in 2011 after arguments with the PCB before becoming T20 captain.