Tap Add new to add a new player to the team. You should check first whether the player played in the league before, and if so, migrate or restore the player instead.
Tap Migrate to add a player from another team, season, or league, to the team. Use Restore instead if the player has last played for your team, but is set inactive.
Tap Restore to reactivate a player and reassign this player to the team. All previously removed players will show in a drop down list, unless they have been migrated to another team in the meantime.
Players cannot be added to a team or migrated after the season cutoff date unless you are an Administrator. Do not attempt to add or migrate players before the new season has started.