Melbourne City have confirmed young defender Nathaniel Atkinson sustained an injury to ligaments in his left ankle during the 5-0 win over Adelaide United on Sunday.
Atkinson was stretchered off late in the match after landing awkwardly while defending a corner.
The talented 18-year-old was encouragingly cleared of a break but still faces a lengthy stint on the sideline.
Atkinson has already begun his rehabilitation at the club, City said in a statement.
The teenager, who has won eight appearances in an impressive first Hyundai A-League season, signed a two-year contract extension earlier this month, pledging his future through to the end of the 2019/20 campaign.