Help me understand substitution rules.

[HollySpringsDawg]

Why is it that if the offense substitutes, the refs stand over the ball to allow the defense to substitute? While the ref is holding things up, the play clock keeps running. When ball is released often not enough time for QB to read defense and react. Shouldn't it be up to the defense to get their guys on in time anyway? We still can sub on defense if the offense doesn't, guys just have to hustle. Maybe the ref holds the ball for 5 seconds max when the offense brings on subs, and up to the defense to get their guys on the field. 

Just don't understand it.

[FeralDawg]

3 Seconds is what the rules I read yesterday said.

[DawgNatty]

There is some gray area around this rule, but, the gist of it involves allowing the defense to sub if the offense does.

The offense controls the snap of the ball and can snap at will once the ball is placed...unless...they substitute. If they run in subs, they must allow the defense to sub also. This is where the "3 second rule" comes into play. Kirby explained it in his press conference following the game. The defense has 3 seconds to decide if they will sub...not to actually sub. Once they make the decision to substitute they have to get their players on and off in a timely manner. Tennessee got flagged because their fat ass defender was loafing off the field. As Kirby explained, teams try to do this all the time to delay the offense. The refs are making sure the offense has time to run the play and not get called for delay.

[FeralDawg]

Thank you. And they WERE loafing coming off the field. Glad they called it.

[kdsdawg]

We got called for a delay of game penalty in this scenario, I think last year. Defense was lagging and clock was running and we only had a few seconds to snap.
Ridiculous.