The Barca skipper has missed the last six matches with a knee ligament injury suffered in the clash with Valencia in October and initial fears were he would be out until the New Year.
However, after making a quicker than expected recovery, the Spain international made his return to full training last week and is now in line to feature when Real Madrid visit the Nou Camp on Saturday.
Boss Luis Enrique said he had wanted to give Iniesta a run out in Wednesday's Copa Del Rey encounter with Hercules but can't as the 32-year-old is suspended.
"Andres is waiting for medical clearance [to return], which is more of a formality really," said Enrique.
"He's training with us and he's in great condition. He can't play [against Hercules] because he's suspended, but he would have had minutes otherwise. He's available [for Madrid]."
Samuel Umtiti could also return to action in the Clasico having recently been sidelined with a hamstring injury, the French defender taking part in training on Monday.