Aiden Bonar during a North Melbourne training session at Arden Street Oval on April 16, 2021. Picture: Getty Images

NORTH Melbourne defender Aiden Bonar will be sidelined from full pre-season training for up to three months after he aggravated an old wrist injury at training last week. 

The injury to his left wrist was assessed over the weekend and it was later decided that he should undergo surgery.

North Melbourne performance manager Daniel McPherson said it was a setback for the 22-year-old but the nature of the injury meant Bonar would be able to retain his fitness base while he recovered.

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"Aiden came back to the club in great nick after the break so it's disappointing for him," McPherson said.

"He suffered a slight injury to the wrist in round five this year but it wasn't enough to sideline him at the time. He was fine heading into pre-season and had been training without any issues until an innocuous incident in a drill last week caused the old injury to resurface.

"He'll have the surgery next Monday, and will be back into his running program shortly after that."

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Bonar came to the Kangaroos from Greater Western Sydney ahead of the 2020 season, joining former Dandenong Stingrays teammate and close friend Luke Davies-Uniacke at Arden Street. 

Aiden Bonar celebrating his first win in his debut game for Greater Western Sydney in 2018. Picture: AFL Photos

He was originally taken by the Giants with pick no.11 in the 2017 NAB AFL Draft and made his debut in his first season with the club. He has since played 22 AFL games, with 16 of those coming as a Kangaroo.

Strong performances at the start of 2021 season had him placed in the top three of the Syd Barker Medal at the end of round six however an ankle injury interrupted his campaign two weeks later. He returned from that early setback to play the last three games of the year.