In team sports, the number worn on a player's uniform is used to identify the player to officials, other players, official scorers, and spectators. The International Federation of Football History and Statistics, an organization of association football historians, traces the origin of numbers to a 1911 Australian football match in Sydney.
You know a superstar athlete has become a legend when his name has become synonymous with his jersey number, and there’s a banner with that number on it hanging in the rafters of every stadium of every team he ever played for. Ninety-nine? That’s Gretzky. Ten? Pele, of course. Forty-two? Jackie Robinson. Twenty-three? Jordan.
A long time ago, when numbers were first placed on [soccer] jerseys so the fans and media could tell who players were from high in the stand, the numbers were handed out based on the starting formation. The first 11 wore numbers 1 to 11, starting with the keeper as the #1 and moving from the back to the front. This is just like the early days of baseball when the batting order wore numbers 1 to 9 based on the place they were hitting. Babe Ruth wore 3 and Lou Gehrig 4 because they hit 3rd and 4th in the Yankee order.
With its roots on college campuses, uniform numbers in professional football were originally assigned at the discretion of the teams themselves. Coaches and staff may very well have given a certain player a number based on his own whims since there were no standard rules in the professional leagues at the time regarding which numbers could go to which position. That all changed in 1952, more than a decade before Vince Lombardi's Green Bay Packers won Super Bowl I.
NFL Numbers are based on the player's primary position on the football team. 1 to 19 – Worn by kickers, punters and quarterbacks. Starting in 2004, wide receivers were also allowed to wear numbers between 10 and 19. 20 to 49 – Worn by running backs, tight ends, safeties and cornerbacks. 50 to 59 – Worn by linebackers and offensive linemen. 60 to 79 – Worn by both the offensive and defensive line. 80 to 89 – Worn by wide receivers and tight ends. 90 to 99 – Worn by linebackers and defensive linemen. 0 and 00 – No longer used after 1973.
Wearing the #10 [in soccer] is saying “this is my team and I am going to kick your butt.” Wearing the #10 means you will carry the load and the burden both on and off the field. The names in this jersey are the all time greats of the game. Forward, attacking mid, central mid, playmaker, sweeper even… The dominator of the game.
The story of Gretzky’s #99 would be boring if he didn’t turn out to be the best hockey player that ever lived. You see, he originally wanted #9 (in honor of his boyhood hero, Mr. Hockey himself, Gordie Howe), but it was already being worn by his teammate on the Sault Ste. Marie Greyhounds of the Ontario Hockey League. So the Great One chose 99 instead, which was only fitting, since he went on to supplant Howe as the undisputed face of the sport.
We also all may recall how Michael Jordan made No. 23 a mystical number. Then, after his first retirement, he returned at the end of the 1994-95 season wearing No. 45, but met failure in the playoffs. He reverted to No. 23 the next season and three more championships followed.
Random cool facts:
1. Japanese baseball players avoid wearing No. 4, pronounced "shi," because it also means "death."
2. Rick Barry wanted 24 when he played with the Rockets, but Moses Malone already had it. Barry dealt with it: he wore No. 2 at home and No. 4 on the road.
3. Mets pitcher Sid Fernandez wore No. 50 because he was from Hawaii, the 50th state.
In Italy, the number 17 carries the same foreboding [as 13 in the US]. Superstar Roberto Donadoni missed the final penalty shot for Italy in the 1990 World Cup loss to Argentina while wearing #17. Four years later, .... team officials give #17 to Alberigo Evani. An outstanding midfielder, Evani pulled a hamstring and missed the final games.
Today the [rugby] player names, positions and numbers worn on shirts are defined by the International Rugby Board (IRB). Players usually have the following position names and numbers although there are some local variations in naming in common use: 1- prop (loose head), 2- hooker, 3-prop (tight head), 4 & 5- lock, 6 & 7- flanker, 8- number 8, 9- scrum half, 10- outside half or stand-off or fly half, 11- left wing, 12- left centre or inside centre, 13- right centre or outside centre, 14- right wing, 15- full back.