The 31-year-old was injured whilst fielding against the Perth Scorchers at Marvel Stadium.
Scans on Monday have confirmed the injury as an ACL rupture.
Maddinson’s rehabilitation plan will be confirmed over the coming days, following consultations with medical staff from the Melbourne Renegades and Cricket Victoria.
“Our thoughts are with Nic and we will continue to support him as he works through his recovery,” Melbourne Renegades General Manager, James Rosengarten said.
“Nic has been a fantastic leader for our team since taking over the captaincy last season and he will continue to play a big role in this team moving forward.”