12th man

[MJT]

Originally Posted by BoBo

I concur with what you are saying

BUT

what if a sub comes in late and the play is being called and the huddle is breaking and he is subbing for someone. As the huddle breaks the sub is leaving the field with no intent to decieve the opponent.

In this case you can not have a penalty.

the offense may be situational subbing and the player is getting to the huddle late.

we are to allow the substitution to be completed as long as it is in a timely manner and not decieve the defense.

back to the defensive play.

you have 12 men.

does the offense have the option to take the results of the play (here they gained 30 yards)
or
15 yards from the previous spot replay the down if it has not resulted in a first down.

No problem with the late substitution you are describing. Before, during, or after the huddle breaks one player can replace another.

For your last question, it all goes back to rule 10-4 and basic spots. A foul simultaneous with the snap is enforced from the previous spot. That is the only option for the IS or IP foul by A or B.