The defender suffered the injury during his side’s loss to West Coast on Monday and is expected to be sidelined for 12 months.
Hawks GM of Football Graham Wright confirmed the sad news in a statement on the club website.
“This is obviously devastating for Sis, his teammates and the wider Hawthorn family,” Wright said.
“He has developed into a leader both on and off field over the last few years, and was having an excellent year personally this season.
“He is a man of great resilience though and we have full faith he will be diligent in his recovery over the next 12 months.”
Sorry Hawks fans – this isn't the news you want to hear. 😓
Wishing @J_Sicily all the best in his recovery. 💛💛💛
— Hawthorn FC (@HawthornFC) August 17, 2020