NFBC Message Boards

New to NFBC here... how does the substitutions work? I have been trying to sub a player in for the scoring period that started today but I keep getting a message that I have to have a player on the DL to sub out. Can somebody explain that rule to me please?

scoring period is monday to monday. like it is telling you- the only players you can sub out now are dl players. to make moves for next week- go to the monday-thursday .