[FormerUmp]

Originally Posted by KWH

The answer is NO! In the NFL, the defense is NOT required to be on the field.

And here is exactly why I say that:

1998 - Bills @ Pats
Drew Bledsoe throws a TD to Ben Coates with no time left to take the lead over Buffalo 23-21. Both teams left the field. The officials then called them back but only the Pats PAT team returns.
The Pats lined up in a FG formation without any Bills on the field. Ball is snapped it to Vinatieri who ran it in for a 2 points. Probably the finest moment in Pete Carroll's Patriot career.
Final: Pats 25, Bills 21

Check out: https://en.wikipedia.org/wiki/Adam_Vinatieri

Look at the 1998 Season and it indicates he scored a two point try.
It is indeed a rarity for an NFL kicker to score a 2-point try, but it has happened.

Here is the story: https://www.buffalorumblings.com/201...xboro-patriots

Hope this helps.

An interesting bit of trivia. Thanks.