The Boeing fix is for both pilots to apply maximum force to the rudder pedals until the rudder 'unsticks'. What happens when it comes free appears to this SLF to be potentially problematic.
The rudder goes to full deflection and the aircraft rolls over and dangerous stress levels are applied to the tail. Assuming this is done at low altitude, full deflection would be available as rudder limiting is normally applied at high altitude.
In the accident involving American Airlines flight 857, overuse of the rudder stressed the vertical stabiliser to the extent that it separated from the aircraft.