The 23-year-old’s injury is another blow to the Suns’ midfield, with key players David Swallow and Jaeger O’Meara already sidelined for the first half of the season.
Hallahan, who was not selected in the senior side for the opening game of the season, was due to undergo surgery on Tuesday afternoon.
“He had an X-ray on the night at Pindara [Hospital] which showed he’s got a fracture in his fifth metatarsal, so that’s the bone on the outside of his foot,” Gold Coast head physiotherapist Adam Russell said.
“He’s upsetting our ankle surgeon, Ben Forster, at the moment, and unfortunately he’ll get that (ankle) screwed this afternoon so he’s looking at about eight weeks on the sidelines.”
Hallahan played 12 games for the Suns last season, after crossing from Hawthorn during the 2014 trade period.