
Lineup lock. Players lock individually when their game kicks off. A player whose game has started cannot be moved into or out of your lineup; players whose games have not yet started remain free to swap.
You set your own lineup. Each manager is solely responsible for setting a valid, active lineup every week. The Commissioner does not set, fix, adjust, or retroactively change any manager's lineup - not for a forgotten start, a player left in on a bye, an injury, or a late inactive. Empty or invalid starting slots score zero, and there are no makeups. Aside from the lock rule above, managers are free to set their lineups however they wish.