Collingwood key defender Nathan Brown will undergo a standard knee reconstruction, ending his AFL season before it even starts.

Scans have confirmed the 22-year-old ruptured the anterior cruciate ligament (ACL) in his left knee during training on Monday.

However, the Magpies ruled out the newer LARS procedure for the premiership backman, opting instead for the traditional knee graft.

There is widespread interest in the LARS procedure because the knee recovers quicker, but the long-term effects of the new surgery remain unclear.

"I'm a bit bemused by the LARS surgery because the media have picked up on this new technique over the last 12 months - that is the biggest question with knee reconstructions these days," Magpies football manager Geoff Walsh said.

"It's not something we've contemplated in the past.

"After consultation with the experts we will go down the path of the normal reconstructions our surgeons have conducted in the past, and will conduct in the forseeable future, based on their expert opinion."

Brown was coming back from off-season shoulder surgery when he suffered the serious knee injury.

"There is never a good time for these things to happen, but to happen before you've played a game in the season and then maybe your whole season is shot would be more hard to handle," Walsh said.

"There was no contact or no contest - you wonder how and why it happens because there is no obvious stimulus or contact to bring it on."

Brown has played 50 senior games for the Magpies since making his debut in 2008, including last year's drawn grand final and the replay, in which Collingwood broke a 20-year premiership drought.

He was rated among his team's best in both of those grand finals, given his stopping job on St Kilda skipper Nick Riewoldt.

Brown did not play in the Magpies' opening NAB Cup fixture on Saturday night, when they downed Carlton and Richmond.

He is likely to have the surgery next week.

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