Kangaroos AFL big man Majak Daw hurts knee

North Melbourne AFL ruck-forward Majak Daw has undergone surgery after tearing his meniscus in the right knee during training.

North Melbourne big man Majak Daw is in doubt for the start of the AFL season after suffering another injury setback.

The 195cm ruck-forward underwent arthroscopic surgery on Friday after injuring his right knee while running earlier in the week during training.

"There was no warning of any issues prior to Monday so this was an unexpected and unfortunate setback," Kangaroos football boss Cameron Joyce said.

"We discovered a tear in his meniscus so he was immediately referred to a specialist."

The injury-prone 25-year-old has managed just 25 games in four seasons but had hoped to cement his spot in the North Melbourne forward line following the departure of stalwart Drew Petrie.

"It's too difficult to put a time frame on his return to full fitness at this stage, but we are confident he'll be available in the opening rounds of the season," Joyce said.