Illegal participation
 

NFHS Rules. Team member # 81 goes out for a short pass near his team's sideline. QB throws the ball deep over the middle to another player. #81 realizes he is not in the play and goes out of bounds to the team bench. Defensive player #40 intercepts the pass. During the run back #40 fumbles the ball near the visitors’ sideline. # 81 comes back onto the field and recovers the fumble. What is the procedure?

Illegal participation on A81 at the spot he re-enters. A can not keep the recovery as they did not recover with clean hands. B will retain possession 15 yards from the basic spot.