 In theory, "dollar defense" (nine backs) and "twoonie defenses" (ten backs) are also possible but, for practical reasons, are almost never used; similar scenarios may involve linebackers replacing defensive linemen.Professional teams may not have enough defensive backs on the roster to play the quarter or half-dollar defenses, so wide receivers sometimes fill the extra positions, particularly in late-game situations when the receivers' offensive skills can be put to defensive use.When the defense concedes short plays, an offense that can practice clock management effectively can score without executing the long pass the defense seeks to prevent.