The Australian international has not featured for the Toffees so far this season after picking up the injury in a pre-season friendly with Werder Bremen.
Cahill is making good progress with the injury and Everton physio Mick Rathbone expects the former Millwall man to be back in action soon.
"Tim unfortunately sustained a disturbance of his fracture site, when he landed awkwardly against Werder Bremen," Rathbone told the club's official website.
"It's not so bad, he's walking round with no symptoms at all now. It's so frustrating. We're looking for 6-12 weeks on that. I know Tim will be banging the door down to start running on it soon.
"Getting him back into training isn't so bad, getting him back running round isn't a problem, but getting him jumping like he does, and landing full force on the outside of his left foot, it's going to be a while before it's going to be strong enough to be able to do that.
"But again the time goes by, he gets stronger everyday."
There was also good news on Victor Anichebe's fitness after he was forced to limp off during Saturday's 1-0 defeat to Reading.
Rathbone says the injury is not serious and that the striker should be back in action soon
"Victor landed awkwardly during the Reading match and jarred his ankle. I have had a look at it this morning and it is a minor problem," added Rathbone.