For example, if a team plays a base 4-3, cover one on first and second down and limits the offense to only one total yard, third down and long is most likely a pass play.
Down and distance determines what coverage and alignment that is shown by a defense, so the frequent change of scheme occurs on each down. For example, if a team plays a base 4-3, cover one on first and second down and limits the offense to only one total yard, third down and long is most likely a pass play. A defense could keep the same alignment or switch to a cover three as the offense brings in two extra receivers. The defense could also respond by shifting to a nickel zone in which there are five defensive backs on the field to account for the pass.