Keys & Movement
If 5 or more are counted in the offensive backfield, drop a flag for an illegal formation foul.
Watch the initial line charge.
Key the end and wide receiver if a defender is covering him tightly. If the end is uncovered, look through to the tackle to read run or pass.
Be alert for quick plays into the line and assist in marking forward progress with the downfield foot.
Check blocks on eligible receivers and blindside blocks by the receiver.
When the ball comes to your side: observe blocking near the neutral zone; on option plays, observe the pitchman and watch for a loose ball; cover the sideline; sound the whistle when dead.
If the ball becomes dead in the side zone, toss it to the Back Judge, Referee, or Umpire for spotting.
Out-of-Bounds / Opposite Side
If the ball goes out-of-bounds: immediately signal time-out; hold the spot and continue to watch action out-of-bounds. Do NOT turn your back on the play.
If the ball goes to the opposite side: move off the sideline no further than the numbers until the down ends. If not responsible for the dead-ball spot, move further in to dead-ball officiate.
Observe action on linebackers and backside pursuit. Watch for late blocks and forearm blows away from the runner.
While moving downfield with the runner, watch for an illegal forward pass or a fumble.
If play continues following an illegal forward pass, drop the penalty marker at the spot of the pass and continue to officiate.