This is from MLB's site about this year's offseason:
Officially, players become free agents the day after the conclusion of the World Series. However, they cannot sign with a new team until five days after the conclusion of the World Series (Thursday, Nov. 10, at 5 p.m. ET).
So does this mean that anyone who signs after Thursday at 5:00 p.m. goes into the pool? Or is there a special exception for anyone who gets a QO? Teams have to offer a QO by Thursday, and then players have a 10 day window to decide.