This setting indicates how you would like to handle players in foul trouble when making substitutions. The more aggressive the setting, the more likely a player will be to stay in the game and play with foul trouble.
For example, if a player picks up 2 quick fouls in the first quarter, a setting of Very Conservative would probably remove that player immediately and keep him out of the game well into the second quarter. But a setting of Aggressive would likely leave him in the game, risking further foul trouble.
NOTE: The Very Aggressive setting will always completely ignore any foul trouble when determining substitutions.
This setting cannot be directly translated to situations (e.g. player will come out until the 2 minute mark with 3 fouls) because there are other factors involved, including depth chart settings, foul trouble of other players and target minutes.