Free agency can be a tricky period to navigate for NFL teams, especially those with top-end pending free agents on their own rosters. These teams must find a delicate balance between retaining the player and not hamstringing themselves in the salary-cap department.
This is why the franchise tag is often the last resort in contract negotiations. Using it ensures that a player won't depart in free agency, but it comes at the cost of a hefty one-year salary.
That salary must be no less than the average of the five highest-paid players at the position.