Big on Big

BOB gets expanded two ways because the protection has two kinds of assignment: Big on Big puts offensive linemen on defensive linemen, and Back on Backer puts a back on a blitzing linebacker or defensive back. Those are not competing definitions. They are the same man-protection rule viewed from its two position groups.

The count is declared before the snap. The quarterback or center identifies the Mike so the line knows which second-level threat joins the down defenders in its count and which threat belongs to the back. In the drawing above, the guards and tackles have the four down defenders, the center has the declared Mike, and the back has the other linebacker.

The declared Mike does not have to be the man the defense calls its middle linebacker; for the offense the name is bookkeeping. If the back's linebacker rushes, the back blocks him. If he drops, the back can release into a route once he confirms the man is not coming, which is a check release.

Being outnumbered and being wrong are different failures. Six blockers against six rushers has the bodies, so a free rusher there means the count or communication broke. Six blockers cannot account for seven rushers. The quarterback has to handle the extra threat through the throw or the protection call. Fronts, dual reads and protection rules vary by system, but the BOB label still describes man assignments rather than a second run-blocking call.