I was informed this is Flavius Palmatus, vicarius (governor) of the Roman province Asia end Vth cent. AD. He is supposed to throw the "mappa" in his right hand into the circus as start sign of the horse races. In his left hand a sceptre, symbol of his authority.
From the Tetrastoon, the agora of four stoas, in front of the theatre, 500 AD. The governor has a fashionable Constantinopelean hairstyle. The statue was on a reused base for a local citizen who was called Flavius Athenesius.