Athletes care about the number they wear on their back. LeBron James is playing with 23 on his back during game time with the Cleveland Cavaliers, but is wearing a number 6 jersey while practicing. Turns out it has something to do with Deion Sanders.
Sanders, maybe the best cornerback in the history of the NFL, played in the NFL from 1989 to 2000 and made a comeback in 2004-2005 with the Baltimore Ravens. During the first 12 seasons of his career, in which he won Two Super Bowls (with the Dallas Cowboys and San Francisco 49ers), made 8 Pro Bowl games and was named to be a first team All-Pro 8 times, he wore the number 21 on his jersey. During his two years with the Ravens, he wore number 37. During practice, he wore the number 2.
But Sanders, who was also a very good baseball players for most of the 1990s, wore a number 2 during practice. He also wore the number 2 during his final season in baseball, playing for the Cincinnati Reds, although he was number 24, 21 and 12 during his baseball career.
When LeBron James played for the Miami Heat (2010-2014), he wore the number 6 jersey.