Is this legal?

[chsbasebal]

A JV team lines up in a legal formation. Prior to putting his hands under center, but after all players are set, the QB yells to one player to "get off the field - We have too many players" As the player sprints for the sideline, the ball is snapped and obviously the "extra" player turns up the field and they throw him the ball.

(Oh, and the sprint to the sideline was correct motion)