Injured reserve list

The injured reserve list (abbr. IR list) is an official designation used by the National Football League (NFL) and National Hockey League (NHL) for athletes who become injured and temporarily unable to play. It is analogous to the injured list in the Canadian Football League (CFL) or the disabled list in Major League Baseball (MLB). The National Basketball Association does not have a direct analog to an injured reserve list, instead using a more general-purpose "inactive list" that does not require a player to be injured.

It is used because the rules of these leagues allow for only a certain numbers of players on each team's roster. Designating a player as "Injured/Reserve" frees up a spot, enabling the team to add a new player during the injured athlete's convalescence. In the NFL, when a player is placed on the list he cannot return to play for the remainder of the regular season; the other leagues allow the player to return to play during the season. The NBA's inactive list is the most liberal as it does not generally require a player to be injured.

A player may be placed on injured reserve if he is unable to participate due to illness or injury, provided that the player had passed the club's initial physical examination at the start of the season. To qualify for the IR due to injury, that injury must be sufficient (in the opinion of the team's medical staff) to render the player unable to participate for the seven days following that injury. Once placed on IR, the team may then replace the player on their roster. The player on IR may not return to active play for seven days, although they may participate in non-competitive events such as practice, meetings, etc.

A team may place a player on injured reserve (reserve/injured list) who is "not immediately available for participation with a club". Generally, these players may not practice or return to the Active List for the rest of the season (including postseason games or the Pro Bowl) in which they are placed on injured reserve, but are allowed to be with the team.

During the preseason, the league also allows players with long-term, but not season-ending, injuries to be placed into one of two designations: physically unable to perform (PUP), for injuries sustained during the previous season or during training camp, or reserve/non-football injury, for injuries sustained outside of team or league activities (despite the name, this includes lingering injuries from college football play, should an injured player be drafted and join the team). Both designations are functionally identical in that the player can be promoted to the active roster by week 6 of the regular season or placed on injured reserve.

...
Wikipedia