In Major League Baseball (MLB), the injured list [IL] (known as the disabled list [DL] prior to the 2019 season) is a method for teams to remove their injured players from the roster in order to summon healthy players.
Players are placed on either the 10-day (prior to the 2017 season, 15-day) or the 60-day injured list, usually depending on the severity and/or recovery time of the injury.
Placing a player on the injured list opens a spot on the active roster. Another player from the minor leagues, free agent pool, a traded player, or a recovered player coming off the injured list may be used to fill this spot. This allows a team to avoid the disadvantage of playing with an incapacitated player on the bench.
The player may not rejoin the active roster until the minimum 10 or 60 days has elapsed; however, a player's time on the injured list may exceed the specified number of days, and, further, if a player is transferred to the 60-day injured list after August 1, he may not return to the active roster that season.
The 10-day injured list does not count the player on the active roster (comprising the 25-man roster until September 1), whereas the 60-day injured list does not require the player to be counted on either the team's active roster or its 40-man roster; however, a team's 40-man roster must be full in order for the option of a placement on the 60-day injured list to be available. A player may be shifted from the 10-day to the 60-day injured list at any time, but not vice versa.
The rule about rejoining the active roster only applies to eligibility to play in a game. Players are permitted to stay with the team and attend games, though players may leave the team to focus on treatment, to avoid traveling with the team on a road trip, and/or for short term minor league rehabilitation assignments to prepare for their return to the active roster.
Alternatively, a team may elect to keep a slightly injured player on the roster but list him as 'day-to-day' to indicate that the medical staff is unable to determine when the player can resume full playing activities. If the injury turns out to be minor, then the player may resume playing immediately without having to serve the minimum term on the injured list; however, depending upon the circumstances, the team may find itself effectively shorthanded in the meantime. This also allows a valuable, slightly injured player to continue to contribute in a limited role, such as pinch hitting. Retroactive placement on the IL may be made at most 10 days after the last time the affected player played in a game. This allows a club to defer the decision to place a player on the injured list until more information can be learned about the extent and impact of the injury.
Starting with the 2011 season, Major League Baseball instituted a new, shorter injured list: a 7-day list specifically for concussions. The idea is to prevent long-term brain damage which may take up to 7 days by current standards, without having to serve the 10-day minimum on the regular IL. If a player is not activated from the concussion injured list after 10 days have passed, he is automatically transferred to the 10-day injured list.
Also in 2011, Major League Baseball instituted a paternity list. This allows a team to replace a player who is an expectant father for 1-3 days on the roster to be available for the birth of his child.
A player may be placed on the bereavement list upon attending to a seriously ill member in the player's immediate family or to a death in the family. The bereavement list may span from a minimum of three to a maximum of seven games. Umpiring's bereavement list for death in the immediate family may span up to a full season.
Minor League Baseball uses a seven-day injured list for all injuries. Players who are on the 40-man roster but get hurt in the minor leagues are placed on the minor league IL, but not on the major league IL. One problem this poses is that a player who is injured in the minors and who would be placed on the major league 60-day IL cannot be placed on the 60-day, meaning the 40-man roster spot is not freed up.
A free roster spot on an MLB club can be strategically valuable, leading to occasional creative use of injured lists by MLB teams and their minor league affiliates (similar to teams strategically appealing or dropping an appeal of a disciplinary suspension, in order align the timing of the sentence to optimize player contribution). Poor performing, slightly injured players might be put on the IL to be assigned to the minors for rehab, when the MLB club might really want them reassigned primarily because of performance, but might not otherwise be able to reassign them due to service time, lack of options, contract stipulations, etc. The Collective Bargaining Agreement between the players and the league contains rules against blatantly "gaming the system."
Players recovering from an injury may appear in a limited number of minor league games while still on the injured list in order to prepare for reactivation. Pitchers may play on a minor league club for up to 30 days; others for up to 20 days.
The term "disabled list" was used as far back as 1887, and was common terminology in MLB for over 100 years until being changed to the current "injured list" prior to the 2019 season. The name was changed after MLB was requested to do so by disability advocates, and also allows the term to be consistent with other professional sports that use an "injured reserve list". Players on the "injured list" are not necessarily injured, some being ill or disabled from playing for other reasons.
The categories and variety of disabled lists have changed numerous times over the years. The 15-day disabled list was introduced in 1966, joining 10-day, 21-day and 30-day options, and the 60-day disabled list in 1990. Prior to 1990, the number of players who could be placed on each list was limited, players with major league contracts were not allowed to go to the minor leagues for rehabilitation, and there was less flexibility about when they could return to action. The 10-day disabled list was dropped in 1984 but restored for the 2017 season (replacing the 15-day option), and the 21-day and 30-day options were dropped in 1990 with the introduction of the 60-day disabled list.