Read If a Defensive Player is in Zone or Man

Three simple and easy ways to tell what defense is being played.

Defensive players lock on to the receiver when playing man. (meaning they follow the receiver during motion) Rather while playing zone the attention isn't on the receiver hardly at all. The defensive player will keep an eye on the quarter back waiting to make the play.
Defensive players will position themselves outside of the receiver when they are playing zone coverage. If they are playing man they will position themselves inside of the receiver.
Defensive players sit low and focused when playing man coverage. When playing zone a defensive player will most likely be standing straight up.