Basketball great Jordan shocked the sport when he announced his first retirement at the age of 30, months after winning his third NBA championship with the Chicago Bulls in 1993. Jordan played some minor league baseball before making his return to the NBA in 1995, going on to win three more championships with the Bulls.
Phelps, the most decorated Olympian of all time with 23 gold medals, announced his retirement following the 2012 London Olympics. The American returned to the pool two years later and qualified for the 2016 Rio Olympics, where he won five more gold medals.
Clijsters won the U.S. Open in 2005 before her first retirement two years later. She returned to the sport in 2009 and won a second major title in New York as an unseeded wild card. She made her second comeback in early 2020.
Clemens first retired at the age of 41 in 2003 after winning six Cy Young awards with three American League ballclubs. He returned to the sport a year later and won a record seventh Cy Young Award, as the top pitcher in the National League, this time with the Houston Astros.
Lemieux's career was blighted by health problems, including a battle with cancer. The Canadian spent three years out of the game between 1997 and 2000, during which he was installed in the Hall of Fame, but returned to the ice for another six years before enjoying even more success as owner of the Penguins.