Danning landed awkwardly after contesting a ball in Sydney FC's 1-0 win over Victory at Epping Soccer Stadium.

After meeting with specialists this morning, Danning will undergo surgery this afternoon and  is expected to be out of action for six to nine months.

"I'm disappointed at the injury because I have enjoyed being part of the first grade squad this year but I know I have to forget my disappointment and focus on doing everything right to make sure I am ready to play at the start of next season," Danning said.

Despite the disappointment, the Young Socceroo is already taking heart from the experiences of senior colleagues who have suffered serious injury, only to bounce back and play again.

"I spoke to some of the senior players this morning who have had the same injury and operation and everybody said they will help me get through it," he added.

Eighteen-year-old Danning played eight Hyundai A-League matches this season, scoring against North Queensland Fury in round one.