Totti sustained the injury underwent surgery on late on Sunday after a challenge by Empoli defender Richard Vanigli left him floored.
The fractured ankle was combined with a damaged ligament.
“There is a fracture to the left fibula with associated lesion of the ligament-capsule at the top of the foot,” explained Professor Pierpaolo Mariani of Roma's medical staff.
The long layoff period raised doubts on whether the prolific forward will be able to recover in time for Italy's World Cup campaign.
Italy coach Marcello Lippi has wished Totti a speedy recovery and said that all the resources will be spared to help him recover.
"I hope the recovery time proves to be a bit shorter," Lippi was quoted as saying in La Gazzetta dello Sport on Monday.
"We will do everything possible. Totti is a great player, one of the most important in the national team. It would be a shame not to have him with us."