A club's Active List (25-man roster) must be submitted to the MLB Commissioner prior to the start of each post-season series (LDS, LCS, and World Series).
1. A player who received a Prohibited Substance Suspension prior to the start of Spring Training, during Spring Training, during the regular season, or during a post-season series (Wild Card, LDS, LCS, or World Series), is ineligible to play in any MLB or minor league post-season game(s) or series in that season, even if the player has completed serving the suspension.
2. All other players on a club's MLB Reserve List (40-man roster), MLB 60-day DL, and Restricted List (extended Bereavement, Family Medical Emergency, or Paternity Leave ONLY) prior to midnight (Eastern) on August 31st are eligible to be included on a post-season Active List (25-man roster), but a player on an MLB club's Disabled List (7-day, 15-day, or 60-day), Bereavement List, Family Medical Emergency List, or Paternity List is eligible to be included on a post-season Active List only after spending the minimum number of days required to be served by a player on that list.
3. Any player on the Disqualified List, Ineligible List, or Restricted List (for any reason other than extended Bereavement, Family Medical Emergency, or Paternity Leave) as of midnight August 31st is ineligible to be included on his club's post-season Active List.
4. A post-season eligible player who is placed on an MLB Disabled List, Bereavement List, Family Medical Emergency List, Paternity List, or Restricted List (extended Bereavement, Family Medical Emergency, or Paternity Leave ONLY) prior to the start of a post-season series can (with the approval of the MLB Commissioner) be replaced on his club's LDS, LCS, or World Series Active List by a player who was on a Reserve List or Disabled List, Bereavement List, Family Medical Emergency List, Paternity List, or Temporarily Inactive List of a minor league affiliate from that organization prior to midnight August 31st. However, a post-season eligible player on the 60-day DL cannot be replaced by a player who was not post-season eligible until the disabled player has served at least 60 days on the DL, and a minor league player must be added to his club's MLB Reserve List (40-man roster) before he can be added to the club's post-season Active Roster.
5. A player on a post-season Active List (25-man roster) who is injured or leaves his club on Bereavement, Family Medical Emergency, or Paternity Leave during a post-season series can (with the approval of the MLB Commissioner) be replaced on his club's Active List prior to the conclusion of that series by another eligible player, or by a player who was on a Reserve List or Disabled List, Bereavement List, Family Medical Emergency List, Paternity List, or Temporarily Inactive List of a minor league affiliate from that organization prior to midnight August 31st. A minor league player must be added to his club's MLB Reserve List (40-man roster) before he can be added to the club's post-season Active Roster.
6. If a player is replaced during a post-season series, a pitcher must replace a pitcher and a position player must replace a position player.
7. If a pitcher or position player is replaced during a post-season series, the pitcher or position player who is replaced is ineligible to be reinstated to his club's Active List (25-man roster) for the balance of that series and the next series (LCS or World Series).