We used to speak of substitute players when a team needed to fill a spot with randoms, what is elsewhere called "ringer", nothing about cheating. There is an Old Norse word or something that is translated "fighter" . I don't remember its spelling and could not find the entry immediately. W would become lost in Norse, I guesd (Odin, Vatenfal). So I maintain the hunch that it is identical to wrestling because that's Ringen in German and wringen in Dutch. Again, allusion to the ring in which they fight is petty. Wrestling has a rich tradition but not endowed with literacy. This could easily lead to confusion next to war. Corrolary, a drug ring is not circular, since border running involves bands of war, though they could do a round call.