12 men on defense

[Coach Murray]

What is the penalty gor this infraction?   Thought it was just 5 yds.

[Bobref]

1 hour ago, Coach Murray said:

What is the penalty gor this infraction?   Thought it was just 5 yds.

If the crew can get the defense counted and confirm there’s 12, and the ball hasn’t been snapped, we’re instructed to shut it down and call a dead ball foul for illegal substitution, which is 5 yds. If you can’t get the play shut down before the ball is snapped, and there are 12 in the defensive formation, then it’s a 15 yd. illegal participation penalty (live ball). If the defense has 12, and one of them is trying to get off, but doesn’t get there before the snap, that’s also illegal substitution, but it’s a 5 yd. live ball foul at the snap.

[Coach Murray]

16 hours ago, Bobref said:

If the crew can get the defense counted and confirm there’s 12, and the ball hasn’t been snapped, we’re instructed to shut it down and call a dead ball foul for illegal substitution, which is 5 yds. If you can’t get the play shut down before the ball is snapped, and there are 12 in the defensive formation, then it’s a 15 yd. illegal participation penalty (live ball). If the defense has 12, and one of them is trying to get off, but doesn’t get there before the snap, that’s also illegal substitution, but it’s a 5 yd. live ball foul at the snap.

Thank you for clarification as well as your commitment to the sport!