Captain John Mensah, midfielder Kevin-Prince Boateng and defender Hans Sarpei watched from the sidelines as coach Milovan Rajevac took his squad through another lengthy training session in preparation for the match at Soccer City.
Persistent back problems mean defender Mensah is restricted in his ability to train and is being helped by a specialist physiotherapist who has travelled from France to treat him.
Boateng, who scored the opening goal in last Saturday's second round win over the United States, picked up a hamstring strain in the match at Rustenburg.
He is having extensive medical treatment in an attempt to be ready for Ghana's bid to become the first African side to reach the World Cup semi-finals.
Sarpei is battling a calf injury that officials said made him a serious doubt. "It doesn't look good for him on Friday," Ghana FA president Kwesi Nyantakyi told Reuters at training.
Gyan, who has scored three of Ghana's four goals at the finals, suffered a scare on Monday when he injured his ankle and had to strap it up with ice to reduce swelling.
On Tuesday he jogged several laps of the pitch at the Mogwase Stadium but did not take part in any practice games.
Coach Milovan Rajevac will have Isaac Vorsah back to replace the suspended Jonathan Mensah in central defence but it remains unclear whether Sulley Muntari will get the midfield role vacated by the suspended Dede Ayew.
Muntari has only played a cameo role at the finals so far after a bust up with Rajevac following Ghana's second group game against Australia in Rustenberg on June 19 where he was only used as a substitute.
Nyantakyi said an appeal to soccer's world governing body FIFA over Ayew's caution against the U.S, his second of the tournament, had been rejected.
Ghana argued he had been wrongly booked because TV replays showed he made no contact with U.S. striker Jozy Altidore but FIFA ruled the referee's decision was final, he said.
