12 players on the field after a timeout

[mbyron]

3.7 COMMENT: A procedure has been adopted to provide an equitable penalty
as it relates to illegal substitution. The following are examples of the most common
situations and rulings:

1. If a replaced player or substitute attempts to leave the field, but does not
get off prior to the snap, the foul is considered as having occurred simultaneously
with the snap and the penalty is enforced from the previous spot.
(3-7-4; 10-4-2a)
2. If a replaced player does not leave the field within three-seconds, it is a
dead-ball, illegal-substitution foul. (3-7-1)
3. If a replaced player or substitute goes off the field on the wrong side of the field
during the down, it is an illegal substitution (live-ball foul at snap). (10-4-4)
4. If an entering substitute is not on his team’s side of the neutral zone at the
snap, illegal substitution is considered to have occurred simultaneously
with the snap. If he then participates, it becomes a live-ball foul, illegal participation.
(3-7-6; 9-6-4c)
5. When a replaced player or substitute leaves on the wrong side of the field
or goes across the end line prior to the snap, it is illegal substitution. (3-7-
2; 10-4-4)
6. If a replaced player substitute enters the field during the down, but does not
participate, it is a foul for illegal substitution by a nonplayer, a 5-yard penalty. (3-7-6; 10-4-5)

In addition, the following chart should help officials distinguish the actions of
various individuals who enter the field, during the down, but do not participate.