Returnee Schalke midfielder Kevin Prince Boateng has been ruled out of the epic world Cup encounter against Zambia in Kumasi, Friday.Boateng has not recovered from an injury he picked up weeks ago and several efforts by the medical team to get him ready for the encounter has failed.The former AC Milan star began slight training, Thursday but could not continue and was made to sit back.He was expecting a return after almost two years self-imposed temporary retirement from the Black Stars.His compatriot, Adam Kwarasey has also been ruled out due to injury.Ghana needs just a draw to book play off qualification for Brazil 2014. Zambia needs maximum points.The game begins, 16:00 GMT Friday.