An �Added� player is not just those players that a manager is receiving in exchange for players he is giving up. When a trade is made that doesn�t involve a position for position exchange, often times the biggest gain and loss will be what players you have to fill the positions you are gaining or losing.
For example, If Team 1 receives Albert Pujols and gives up Nick Johnson and Jose Reyes this trade might be equal, it might not be because in reality, it doesn�t just matter the players exchanged, it matters what is being Added and replaced:
Team 1 exchanged Nick Johnson�s numbers for Albert Pujols� at first base� which obviously is a pretty major increase in Fantasy Points. Now, Team 1 also lost Jose Reyes, which is a big loss, but look at the difference between the fairness of the trade depending on who Team 1 is replacing Reyes with. If Team 1 has Miguel Tejada waiting in the wings, that trade is immediately terribly unfair because Team 1 lost nothing from Jose Reyes to Miguel Tejada, but gained a great amount between Albert Pujols and Nick Johnson. But now look what happens if instead of Miguel Tejada, team 1 is forced to start Royce Clayton. Suddenly, the trade seems more fair � The difference of Albert Pujols and Nick Johnson is relative to what he losses between Jose Reyes and Royce Clayton. On top of this however, is what Team 2 would be gaining by losing what they got in Albert Pujols and acquiring Jose Reyes � but it�s the same principle, an �Added� player isn�t just who you are trading for, it�s also the players that you plan on filling a position lost.
The issue is, of course, we don�t know all the players that will be added, and it is ridiculous to think that a player will be �honest� and say they will be using some terrible player so the trade is evened out. And so, to fix this problem, when evaluating a trade, the player being considered to replace a lost position will be the best available player to that manager (either via, Free Agency, Triple A, or on his Bench � judged off of a Player�s Price). And so, regardless of who the manager �intends� to use, the trade will be evaluated based on who the best in the market is.
Similarly, a �Replaced� player isn�t necessarily the player that is dropped by a team who is receiving more players than his roster can hold. A �replaced� player is any player who is now being replaced in the starting lineup or on the bench� Platooning does not matter.