You have to wait until the following week to replace them. You have until the end of Sunday (I think it's around 2ish am EDT Monday morning or something like that) to make your roster changes for the week. After that, you can't make any changes for any reasons. They would release and pick-up players daily to maximize the # of players that they would have playing each day. The strategy is to have more players playing than your opponent. The result was that there would be a large # of players on waivers at any given time, so if you did have to pick-up a player due to an injury, your pickings were pretty slim and if you wanted to pick up anyone half decent, you'd have to waste a waiver claim on them and not get to use them until they cleared. Personally, I very much dislike that type of play. I have enjoyed weekly lineups in previous leagues that I've been in. The biggest downside is the aforementioned injury issue. Limiting roster moves and going with daily lineups would be another option, but IMO, the limit would have to be pretty low in order to really eliminate "Tatering" as an option. At the end of the day, I'm still going to play regardless of the rules we decide to go with, those are just my 2 cents.