What's a Nickel Cornerback?

In American football, a nickelback is a cornerback or safety who serves as the additional defensive back in a nickel defense.

What is a nickel defense in the NFL?

In American football, a nickel defense (also known as a 4–2–5 or 3–3–5) is any defensive alignment that uses five defensive backs, of whom the fifth is known as a nickelback. The original and most common form of the nickel defense features four down linemen and two linebackers.

What is a nickelback on a football team?

When a team's in quarters, the nickelback is mostly an underneath defender responsible for defending the perimeter. Against any two-back set by the offense or a formation with only two receivers to one side, the nickelback is typically going to be playing a role in stopping the run in a quarters defense.