North Melbourne defender Aaron Mullett is set to miss the opening seven rounds of the 2015 AFL season after undergoing surgery on his left shoulder.

The 22-year-old had been carrying the injury towards the end of last season but was given the all-clear to play on this year.

However, the club said Mullett had suffered further damage in the past two months and needed surgery on Monday to repair a torn labrum.

“The consensus was that Aaron would be fine to get through another season and we’d review him again at the end of the year,” director of sports science and training services, Steve Saunders, told the club’s website.

“New symptoms developed, we’ve reinvestigated these and found new pathology in his shoulder joint.”

The 184cm backman played 17 games last season, but only four of the Kangaroos’ last nine.