on optional assignment with a minor league team 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." History 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 unable to play 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. See also Injured reserve list References Baseball rules Baseball terminology Sports injuries