Illegal substitution?

[Cobra]

Originally Posted by ppaltice

If A12 lines up or if he communicates with the team, another player must come off. Read 2-32-15 to see what qualifies for being a player. If A12 neither lines up in a position, or communicates with a teammate or official, he can leave with no foul.

You are right that he is not a player until he does those things. But a nonplayer cannot be outside his team box unless to become a player or to return as a replaced player. This guy is not entering the field to become a player, he is entering the field to look at signals. If this were legal a team could have 20 guys run all the way out on the field between downs, not communicate with players nor enter the huddle, and then run all 20 back off the field.