The secondary is responsible for:
- preventing a score from the offense
- Countering receivers on the offense
- Sacking the quarterback (ball carrier)
- Forcing turnovers
There are special names for defenses that require extra defensive backs: five DBs is a "nickel" scheme, while a "dime" defense adds a sixth defensive back. These extra defenders are known as the nickelback and dimeback, respectively.
The cornerback is a defensive back who protects against the pass and counters wide receivers on the offense. Cornerbacks must follow receivers that run routes on the field to prevent a pass from being caught.
Strong Safety vs. Free Safety
Football Strong Side