Rules Analysis
Picks:
Initiating contact with a disc in a player's possession is a foul. Sustained contact with, and control of, a non-spinning disc is required to establish possession (3.J). A player may not call a strip if they had only momentary contact with or lacked control of the disc prior to an opponent contacting the disc.
A pick occurs whenever an offensive player moves in a manner that causes a defensive player guarding (3.E) an offensive player to be obstructed by another player. Obstruction may result from contact with, or the need to avoid, the obstructing player.
A pick can be called only by the obstructed player and must be announced by loudly calling "pick" immediately after it occurs.
In addition, the obstructed player is then allowed to move to recover the relative position lost because of the pick.
So if the disc is returned to the thrower, everyone resumes the locations they occupied at the earlier of the time of the throw or the time of the call.
During any stoppage of play, opposing players may agree to slightly adjust their locations to avoid potential imminent picks.
Then the picked defender catches up the relative position lost because of the pick. If they were trailing by 9 feet, then they get to catch back up to 9 feet away, but does not get to set up right next to the offensive player.