After leaving the Premiership and West Ham, Mladen Petrić found a new challenge in the Greek capital, Athens, and chose to defend the colours of Panathinaikos.
Petrić agreed to a one-and-a-half-year contract.
Panathinaikos has already had two Croatian internationals on its roster, Gordon Schildenfeld and Danijel Pranjić.
Mladen Petrić was capped 45 times for Croatia, scoring 13 goals.