COLLINGWOOD defender Lynden Dunn will miss the rest of the season after scans confirmed he has ruptured the anterior cruciate ligament in his left knee.

The 31-year-old left the field in the third term of Saturday night's win over Gold Coast at Metricon Stadium after landing awkwardly in a marking contest with Sun Nick Holman.

If he has a traditional knee reconstruction, Dunn, whose contract expires at the end of this year, will likely be sidelined for up to half of next year as well.

The negating defender has been an important part of the Magpies' backline this season, with injuries to Darcy Moore and fellow veteran Tyson Goldsack.

Dunn has played every game this season where his leadership and defensive experience have been vital for a young Collingwood backline.

With Moore likely to resume in the VFL this week after a long-term layoff with a hamstring injury, and unavailable for AFL selection, the Magpies may turn to mature-age rookie Brody Mihocek who could be pushed into defence to cover the loss of Dunn.

Dunn joins Daniel Wells (foot) and Goldsack as those Magpies who have been ruled out for the season, with star midfielder Adam Treloar (hamstring) to be sidelined until at least September.