The centre half was taken to hospital in Dublin immediately afterwards and X-rays revealed the fracture.
Lucas Radebe came on to replace Duberry, the South African continuing his comeback after a summer operation to clean out debris from his knee but the former South Africa international will struggle to be fit for Sunday's season opener against Newcastle.
Skipper Dominic Matteo began the game at left back, but now looks certain to partner new signing Zoumana Camara in the centre of defence when Leeds kick off the new season against Newcastle on August 17.