Injured reserve

The injured reserve list is a list of reserved players who are injured and unable to play for a period of time, used most prominently in the National Hockey League (NHL) and National Football League (NFL). It is used because these leagues have a maximum number of players on the team roster, so placing a player on the injured reserve list frees up one spot. In Major League Baseball (MLB), a similar list called the disabled list is used. Also, in the National Basketball Association (NBA), the Inactive List is the rough equivalent of injured/disabled lists of other sports. In the NFL, when a player is placed on the list called "Reserve/Injured", he cannot play for the remainder of the 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.

NHL rules
In the event that a player is injured and a Club wishes to place him on the Injured Reserve List the Club must follow these procedures:

Players on Injured Reserve may attend team meetings and meals, travel with the team and participate in practices.
 * 1) A club may place a player on the Injured Reserve List if such player is injured, disabled or ill and unable to perform his duties as a hockey player after having passed the Club's initial physical examination in that season.
 * 2) A player who has an injury that renders him physically unable to play for a minimum of seven days after that date of the injury can be placed on the Club's Injured Reserve List. Once a player is placed on the list, the Club may replace said player on its NHL roster with another player. All determinations that a player has suffered an injury warranting injured reserve status must be made by the Club's medical staff and in accordance with the Club's medical standards.
 * 3) A player placed on Injured Reserve is ineligible to compete in NHL games for a period of not less than seven days.

NFL rules
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) that they are placed on injured reserve, but are allowed to be with the team.

Starting in 2012, the NFL and the NFLPA reached an agreement allowing one player placed on injured reserve to be brought back to the active roster. Provided the provisions that the player was on the final 53-man preseason roster (A rule exempted for the 2012 season), and that the injury is deemed to keep this player unable to practice or play football for an estimated six weeks, the player may be allowed to practice after Week 6, and be activated to play after Week 8.

Teams may also place a player on injured reserve with a minor injury designation, but the team must release the player once he is healthy.

NBA rules
Due to abuses in the use of the injured reserve list, where some teams found convenient to use the IR to stash players without independent medical oversight, the injured reserve has been renamed the Inactive List with the last collective bargaining agreement. Starting in the 2005–2006, players can enter the inactive list one hour before tip-off for as little as one game. The inactive list has a minimum of one player and a maximum of three, subject to hardship rules when a team with three injured players already on its inactive list has a fourth player injured. Players sent to the NBA Development League will continue to count on a team’s inactive list.