<P> A team may keep an injured player on the roster but keep him listed as' day - to - day' to indicate that the medical staff is unable to determine when the player can resume normal playing activities again . If the injury turns out to be minor, then the player may resume playing without having to wait to come off the disabled list; however, depending upon the circumstances, the team may find itself effectively shorthanded in the meantime . </P> <P> Players recovering from an injury may appear in a limited number of minor league games while still on the disabled list in order to prepare for reactivation . Non-pitchers may stay in the minor league club for up to 20 days; pitchers for up to 30 days . </P> <P> 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 . </P>

When did the 10 day disabled list start
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