Australian cricket authorities confirmed scans on Wade's ankle revealed a sprain in the joint, throwing him into extreme doubt for the Third Test against India starting on Thursday.
Wade, 25, hurt his ankle while playing basketball in Chandigarh on Saturday.
Veteran Haddin will fly to India on Monday to join the flailing Aussie campaign, Cricket Australia declared in a statement.
"Cricket Australia advises that Matthew Wade’s scans have confirmed a sprained right ankle," the statement said.
"Given the uncertainty of Wade’s availability, Brad Haddin will fly from Australia to Mohali today to join the squad."
Australian team physiotherapist Alex Kountouris revealed the seriousness of Wade's ankle problem.
“Matt has a complex ankle injury which has been confirmed by the scans and at this stage is in doubt for the Third Test starting on Thursday," Kountouris said in the Cricket Australia statement.
"A final decision on whether he will be available for the Third Test will be made closer to the match.”