Captain of the Pilots for three straight seasons, Wintering was hurt in Thursday's game against San Francisco, and an MRI on Saturday confirmed an ACL tear.
Wintering started in 110 career games with Portland and averaged 14.1 points and 5.2 assists. He finishes with 568 career assists, five shy of the school record held by Darwin Cook. He also ranks second in career steals with 177 and fifth in points with 1,548.
He averaged 19.5 points and 5.6 assists a game this season.
"I was given an opportunity here, made the most of it, and played every game as if it were my one and only," Wintering said. "I will continue to be a part of the team and cheer on my brothers every night, doing all I can to be a leader and continuing to build the basketball program."