if the impact of the ball hitting the ear forced air into the ear canal, thus creating undue pressure, damage could result, in the same way someone getting their "ears boxed" [very sad childhood memories of ignorant parents who loved to 'box' ears as a punishment - e.g. a slap against the side of the head where the hand covers an ear when it hits and causes ringing]. Any time there is ringing in the ears there is nerve damage.