Pre-snap realignment

[ajv]

2nd & 10 from A-25. Team A players break their huddle and set up in a formation with six men (left to right - A72 A62 A52 A63 A73, and A83) on the line. The five backs (clearly off the line) are A82, A42, QB A7, A22, and running back A23. The players are set in this position for two seconds. Then A82 realizes he should be on the line. He moves forward to the line, then adjusts to the left widening his position. He stops, shoulders approximately parallel, and half a second later the snap occurs. A7 hands the ball to A23 who is tackled at the A-31.

2nd & 10 from A-25. Team A players break their huddle and set up in a formation with seven men (left to right - A72 A62 A52 A63 A73, A83 and A82) on the line. The four backs (clearly off the line) are A42, QB A7, A22, and running back A23. The players are set in this position for two seconds. Then A82 realises he should be on the left side of the line. He comes off the line (never stopping) and runs behind the linemen and QB. When he reaches the left side of the line, he moves forward to the line and adjusts to the left widening his position. He stops, shoulders approximately parallel, and half a second later the snap occurs. A7 hands the ball to A23 who is tackled at the A-31.

[Legacy Zebra]

No foul, 1/10 @ A-31 in both. In both cases, the shift ended when all players were set. If A82 is the only one moving, the one second rule no longer applies because it is not a shift by definition. At the snap, both formations are legal. So we’ve ruled out illegal formation because they only have 4 backs and have 5 properly numbered linemen, nobody is in motion at the snap, and all shifts have ended. This is a legal play.

[ElvisLives]

2nd & 10 from A-25. Team A players break their huddle and set up in a formation with seven men (left to right - A72 A62 A52 A63 A73, A83 and A82) on the line. The four backs (clearly off the line) are A42, QB A7, A22, and running back A23. The players are set in this position for two seconds. Then A82 realises he should be on the left side of the line. He comes off the line (never stopping) and runs behind the linemen and QB. When he reaches the left side of the line, he moves forward to the line and adjusts to the left widening his position. He stops, shoulders approximately parallel, and half a second later the snap occurs. A7 hands the ball to A23 who is tackled at the A-31.

Whether his movement was continuous, or if he stopped in the backfield is immaterial, if he is the only A player moving after all of Team A has set for one full second. As Legacy says, a single player moving after Team A has set for one second can do whatever he wants, as long as he doesn't commit a false start. He may continue his movement (smoothly), or stop - no amount of time required. He may stop, then start again, stop again, etc., as long as he doesn't commit a false start. In this example, since he never stops until he gets to his final position, he'll need to be on the line and stopped when the ball is snapped. Otherwise, he would be guilty of an illegal motion foul, being in motion from the line. If he stops in the backfield - becoming a back - then moves to the line, he becomes a lineman, again, and he must stop before the ball is snapped, or he'll commit a foul for illegal motion. If he stays in motion (from the line) and the ball is snapped (whether he is in the backfield or on the line), he commits a foul for illegal motion, having gone in motion from the line. If he stops in the backfield - becoming a back - and stays in the backfield (even if he goes in motion again), his team commits a foul for an illegal formation (more than four in the backfield).