What makes fantasy football even more fun is the ease with which you can add and drop players from your roster. It allows you to, with just one click of a button, drop a player from your team, and with one more click, add a player. Adding and dropping players happens so frequently and so quickly every week that you must always be on high alert in order to get the best players.
The way adding and dropping players works is, if your team is at the maximum amount of players, and you would like to add a player, you must drop a player that is currently on your team. The league's "free agent pool" is where all the players not on teams can be found.
Though it is not wise, it is not required that you add a player immediately after you drop one. And if you have an open roster spot already, you would not need to drop a player in order to add a new.
Every league might be different, however, most leagues set a cap for the amount of different players you can add to your roster in one week.
There is also a rule in all fantasy football leagues that you cannot add a player once their game has begun. Meaning, if it is 2:00 pm and you wanted to add a player whose game began at 1:00, you must wait until the week is over to attempt to add him to your team.
There is a science when it comes to deciding which players to add or drop, and when to do it. Often times players who have good matchups in a given week (ex: a running back playing against a team with bad defense) will be picked up quickly. Players who will also fill in as the primary player at their position in place of an injured teammate are also often picked up swiftly.
Deciding which players to drop from your roster can be tricky. If you have a high number of players at one position, you can afford to drop the weakest of the bunch in order for your team to get better a position you might consider a weakness.