A player placed on the Disabled List (MLB 15-day DL or minor league 7-day DL) or Special Disabled List (MLB 7-day DL for players who have suffered a concussion) does not count against his club's Active List, but he does count against his club's Reserve List. As long as the player did not appear in a game during the retroactive period, an MLB 15-day DL assignment can be backdated up to ten days during the season, and to a date no more than nine days prior to the start of the regular season if the player is placed on the 15-day DL during Spring Training. A 7-day DL assignment can be backdated no more than four days.
A player's assignment to the MLB 7-day DL (for MLB players who have suffered a concussion) can be renewed once. If an MLB 7-day DL assignment is renewed and then the player is not reinstated within 15 days of initially being placed on the MLB 7-day DL, the player is automatically transferred to his club's 15-day DL.
A player placed on the Emergency Disabled List (60-day DL) does not count against his club's Active List or Reserve List. A player can be placed on the MLB Emergency Disabled List (60-day DL) during Spring Training or anytime during the MLB regular season (a minor league player can be placed on a minor league club's 60-day DL only during the regular season), and a player can be transferred from the MLB 15-day DL to the MLB 60-day DL (or minor league 7-day DL to minor league 60-day DL). However, a player cannot be moved back to the MLB 15-day DL (and a minor league player cannot be moved back to the 7-day DL) once he is placed on the 60-day DL, and a player cannot be placed on the 60-day DL or transferred to the 60-day DL from the MLB 15-day DL (or minor league 7-day DL) unless his club's Reserve List is full.
For a player who is transferred from the MLB 15-day DL to the MLB 60-day DL (or from a minor league club's 7-day DL to the minor league club's 60-day DL), time spent on the MLB 15-day DL (or minor league 7-day DL) prior to being transferred counts toward the minimum 60 days a player must spend on the Emergency Disabled List.
All players on an MLB 60-day DL must be reinstated to the club's MLB Reserve List (40-man roster) no later than 5 PM on the 5th day following the conclusion of the World Series and all players on a minor league 60-day DL must be reinstated to the minor league club's Reserve List no later than the day after the conclusion of the MLB regular season, even if the player did not spend 60 days on the DL.