Injury Reserve is a term that refers to a list of players who have suffered injuries and become unable to play in North American professional sports leagues. The exact name of the list varies by league; it is known as "injured reserve" in the National Football League (NFL) and National Hockey League (NHL), the "injured list" in the Canadian Football League (CFL), and the injured list (historically known as the "disabled list") in Major League Baseball (MLB) . The Reserve/Injured List, better known as injured reserve or IR, is a list for players who have suffered a football injury that makes them not immediately available to their team. When a player is on injured reserve, he is not eligible to play for his team. Theres no limit to the number of players who can be placed on the list, but there is a cap on those "designated to return" from the list.

Injured reserve lists are used because the rules of these leagues allow for only a certain number of players on each teams roster. Designating a player as "Injured/Reserve" frees up a roster spot, enabling the team to add a new replacement player during the injured athletes convalescence. The NFL has several designations for players who are unable to perform, including the PUP (Physically Unable to Perform), reserve/non-football injury, and reserve/non-football illness. Players on IR don’t count against the active roster. If a player is placed on this list before the regular season begins, he’s forced to miss the entire year. When a player is cleared to practice, it activates a 21-day window during which the player must be activated to the 53-man roster or be placed on season-ending injured reserve at the conclusion of that three-week period.