Magpies' Dunn suffers another knee blow

Collingwood's Lynden Dunn must undergo a second knee reconstruction within a year after re-injuring his knee in his first competitive game back.

Magpies defender Lynden Dunn has suffered a knee injury during his comeback from surgery. (AAP)

Luckless Collingwood defender Lynden Dunn must undergo another reconstruction after re-injuring his knee in his first match back.

Playing in an VFL pre-season match on Thursday afternoon, Dunn suffered the same injury to his left knee, rupturing his anterior cruciate ligament (ACL), and will have surgery next week.

He initially suffered the injury in round 15 last season.

Magpies coach Nathan Buckley said Dunn's injury was discussed before his side's 44-point AFL win over Richmond on Thursday night.

"We didn't mention it pre-game but it filtered through to the boys before they took the field," Buckley said.

Dunn has played 31 games in two seasons with the Pies since crossing from Melbourne.

"Dunny is a much-loved member of our football club," Buckley said.

"He gives so much of himself and he's contributed so much since coming across.

"We really value what he brings to the table on and off the field. His teammates will rally around him."