Single-Season Association teams consist of a 40-man roster divided into an active roster and a reserve roster. (In Career Associations, you have an additional 10-man Low Minors roster.) The active roster holds the players who are available for use during games, and the reserve roster contains players on your top minor league team (AAA) or on the Disabled List (DL). From Opening Day until August 31, the active roster can have a maximum of 25 players. After September 1, teams may expand the active roster to as many as 40 players by promoting players from AAA and the Disabled List. The total number of players, however, still may not exceed 40.
You may move players between the active roster and AAA freely at any time. (Exception: During the playoffs, you may only promote a AAA player to replace an injured player.) You may place injured players on the Disabled List (DL) at any time, but once placed on the disabled list, players must remain there at least 15 days. A maximum of 15 players may be on the DL and at AAA at any given time.
In a Career Association, each team also has a separate Low Minors roster, which may have up to 10 players. This represents the teams farm system. Players are assigned to the Low Minors when drafted in the June Amateur Draft. Players may be promoted from the Low Minors to the 40-man roster at any time, but once promoted, they may not be returned to the Low Minors roster. A player under the age of 26 may, however, be released to the free agent pool, then re-signed one day later and assigned again to the Low Minors roster. Of course, the player may be signed by another team before the original team can re-sign him.
A player traded from a teams Low Minors roster may be placed on the new teams Low Minors roster or the major league roster, but a player traded from a major league roster may not be placed on his new teams Low Minors roster.
To move players from roster to roster, the team must be human-owned. Select Reassign Players from the Team Menu. For more information, see Reassigning Players.