One or the Same

A riddle: Uncovering identity shall be your task A pseudonym to find is all I mask To find my other half you must explore Three hints unveal a poet way off course The first is simpler than the pair in tow A verse nay, question less of to than fro One word is the title of my very first posting And in it I'm very prone to shallow boasting The second quandary of this brainless snag Puts up a somewhat recent warning flag The last piece that my persona wrote Reveals a flatness ancestors denote As for a clue to my other name A retired baseball icon's nick of names Sharing with a sandwich of the king A record broke in autumn, one last swing The last puzzle revealed only the first part The second of my name lives in all hearts This is the title given to a devotee Not of religion, but players we see