While you can never enter picks for games that have started, the pool Pick Deadline is the absolute latest time people can enter picks.

Pool Settings - Pick Deadline

Use this page to change your pick deadline. The pick deadline is the latest time that people can enter or change picks. Once a game starts, even if it's before your pick deadline, the picks for that game are locked. That means you can use a Sunday deadline all year, even if there are games earlier in the week.

Pick Deadline

Note: Picks are never allowed for games that have already started.

Current Setting: The pick deadline for your first week is: Sunday, Sept 13 at 10:00 AM Pacific