The incident happened early in the second quarter, when Rams quarterback Joe Milton threw a deep pass to Johnathan Mingo. As Lamb, who was not in uniform, pointed toward the end zone in celebration from the sideline, he turned his back to the field and collided with an official sprinting down the boundary. Lamb fell face-first to the turf.
Officials flagged Lamb for unsportsmanlike conduct, but the NFL opted not to issue a fine, which is typically assessed for such penalties.
The league did not provide an explanation for the decision, though the collision appeared to be accidental.