North Melbourne defender Marley Williams will miss the rest of the 2017 season after being ruled out with a back injury.

Williams hasn't played for the Roos since round 14, but played in the club's opening 13 games of the season after making the move from Collingwood at the end of the 2016 season.

The 24-year-old will require surgery on his back, but the club's medical team will also repair a shoulder injury he has been carrying since almost the beginning of the season.

“Over the past six weeks, we’ve tried numerous non-surgical treatments for Marley but without the desired results,” North Melbourne general manager of football Cameron Joyce told

“The last resort was and always has been surgery, but unfortunately we’ve run out of time to get Marley back before the end of the year and will now focus on getting him right for the 2018 pre-season.

“This will mean a likely procedure on his back, but first we’ve opted to get his shoulder repaired which he’s been carrying since Round 7. On medical advice, these operations can’t be conducted simultaneously.”

North Melbourne have also confirmed forward Jarrad Waite will miss the next fortnight with a calf injury.

Waite injured his troublesome calf in his side's win over Melbourne on Saturday, and will now miss matches against Collingwood and Hawthorn.