Ghana defender Baba Rahman had a life-threatening injury during the Greek Cup semi-final clash between Panathinaikos and PAOK.
The defender lost consciousness after colliding with an opponent.
He was, however, treated on the field and regained consciousness minutes later.
Baba Rahman was later transported from the field in an ambulance and is currently undergoing further treatment in the hospital.
The incident occurred in the 115th minute of the match, which had gone into extra time following a 2-2 draw in regular time.