Cacau picked up the injury in training last week and was replaced by Miroslav Klose in their 4-1 win over England. Klose is expected to win his 100th cap on Saturday in Cape Town.
"Apart from Cacau, all other players are participating in training. He is doing some light running and therapy. But today and tomorrow it will not happen (training with the team)," coach Joachim Low said.
"So he is also doubtful for the weekend. The final decision will be taken on Friday," Low said.
"I expect an unbelievably tight match as we cannot allow ourselves any mistakes because for any mistake we make, they will punish us in an ice-cold way. They are the top favourites for the World Cup. They have so many players able to score."
"Argentina can be hurt," he said. "We have found some details of their weaknesses but I am not going to elaborate on that."
"If we needed a note in 2006 for the penalties this time we need a whole catalogue if you see the quality of players they have in the squad," Low said.
