Jersey number selection in the National Hockey League is heavily shaped by league regulations, historic retirements, and traditional positional customs that render certain digits exceedingly rare or entirely unavailable. The absolute rarest numbers to see on an NHL ice surface are zero and double-zero, both of which are strictly banned by league database regulations and cannot be assigned to any active player. Furthermore, number 99 is entirely retired league-wide in honor of Wayne Gretzky, meaning no active player across any franchise can ever wear it. Beyond those universally banned digits, high or unusual numbers outside traditional hockey formatting—such as triple-digit numbers or negative numbers—are entirely prohibited by the league's administrative rules, leaving players to choose standard whole numbers between 1 and 98.