12 players on the field after a timeout

[The Roamin' Umpire]

Originally Posted by Canned Heat

Correct.

No "substitution" was made after the RFP was whistled....which would've allowed the new 3 second provision to carry into it with one making for the sideline.

Note that 3-7-1 says nothing about the RFP; all it says is "between downs."

If the coach comes onto the field for the timeout, the wing for that sideline should be watching the huddle. As soon as it has 12 players and no one's leaving, the covering official needs to get the coach's attention and tell him he's got 12 players - get one off. If the coach ignores the request, count three seconds (silently) and toss the flag; in practice, this doesn't happen, as the coach's response is nearly always "WHO'S OUT HERE WHO'S NOT SUPPOSED TO BE?!!"

If the conference was taken at the sideline, then R & U are counting as they come away from the sideline. I count to 12, check that my partner isn't signaling 11, count to 12 again, and then tick off three seconds in my head. If no one's leaving by then, whistle and flag.

The original poster hadn't even counted to 12 once before the replaced player starting running off. No flag from me.