[ChickenOfNC]

Originally Posted by Mike L

Yes, in this case A can shift all they want to create and/or remove eligibility due to position. If the numbering exception is never in use prior to the snap, why would any of the restrictions that come with using the numbering exception apply?


Snapper eligibility is only addressed for downs 1 thru 3. Since the snapper is the only numbering exception allowed and he must be between the ends, he must be ineligible at the snap.
On down 4 or on a try, the rule is silent regarding eligibility. So the snapper can be eligible as long as he is eligible by both number and position. In your example, numbers 21 & 34 will always be ineligible at the snap regardless of any shifts.

Just FYI, 21, 34, and 81 are ineligible regardless of shifts.