It implies his current moniker is something he would prefer not to be called. It could be some physical attribute but rather than guess at that I'll just assume it is the nickname so many folks get stuck with "The Kid." I've personally known folks who were over 70 years old who were branded with that. I survived till I was over 24 with that name and some folks "in the biz" only know me by that.
The cure for anything is salt water -- sweat, tears, or the sea. - Isak Dinesen (pen name of Karen Blixen), author (1885-1962)