Referees travel in crews across all levels of organized football and receive grades on their performances. With so many official on the field, though, it can be tough to tell who's who. To be easily distinguishable to coaches, players and fans alike, each referee has a uniform number and letters to identify him and his position.
Each NFL referee has his own jersey number for the same reason a player does: identification. NFL players have number limitations based on their positions, but referee numbers are randomly assigned, or can be chosen with the permission of the NFL. The numbers for referee uniforms are also allowed to go into the hundreds. The lowest-numbered official in 2012 was Craig Wrolstad's No. 4, while the highest was Pete Morelli's No. 135.
Along with the distinguishing numbers on a referee jersey come a series of letters. Each set of letters denotes a position: referee (R), umpire (U), head linesman (HL), line judge (LJ), field judge (FJ), side judge (SJ) and back judge (BJ). Each position comes with its own responsibilities throughout the game. The most noticeable for viewers is the referee. These head officials are the faces that NFL fans will likely recognize. They are responsible for announcing penalties to the crowd and TV audience.
Referee uniforms have changed throughout the years. NFL officials originally wore white shirts, black pants, black bow ties and white hats, with no distinguishing markings. Because they were frequently mistaken for players of the home team -- which also wears white -- the vertical stripes were added. NFL referees have worn variations of the black-and-white striped and numbered uniforms since 1945.
With seven officials in action at any given time, there are a lot of calls to keep track of. Each "crew," as it's called, in the NFL, is headed by a lead referee. After each game, each referee is rated for every call, according to former NFL referee Allen Baynes. For incorrect calls, the referees lose points off their said grade. Those grading the referees will use jersey numbers to distinguish who made the call. The grade is used, most notably, to determine which referees get called upon for playoff contests.
Through the Ranks
Referees must begin at the high school and college levels before making it to the pros. According to a 2012 article in the "Christian Science Monitor," officials at the high school level and above have a .17 percent chance to make it to the NFL. While there are many variations of the rules, procedures and uniforms between high school, college and the NFL, the jersey numbers and letters all serve the same purpose.