PROMISING North Melbourne forward Kieran Harper will have to be eased into the pre-season after undergoing surgery on his left ankle this week.

The 21-year-old had an arthroscope to repair a problem that emerged during the season, after the injury failed to heal itself with post-season rest.

He will now be on modified duties at the Kangaroos' altitude camp in Utah in November, but will be fully fit for the start of the 2014 season.

All the clubs' summer training plans

"It's all gone really well," North Melbourne director of medical services Steve Saunders told NMFC.com.au.

"Ideally it would have been good to have had the surgery sooner, but sometimes you need to give these things time, because you don't want to operate on absolutely everything that comes under your nose.

"His Utah program will be modified somewhat – he won't be able to do the volume of running and weight-bearing work we'd planned.

"But in terms of what Kieran needs to get out of it in order to be ready for next season, it should all be fine."

It was Harper's second bout of post-season surgery, having earlier gone under the knife to repair some minor elbow damage.

North Melbourne players will depart for Utah on November 15, spending three weeks training at altitude.

The entire playing list will make the trip, with skipper Andrew Swallow (Achilles) and big man Majak Daw (knee) to be among those joining Harper on modified duties.

A former first-round NAB AFL Draft pick, Harper has played 40 senior games for the Kangaroos since his debut in 2011, but only three of those were this season.