MELBOURNE rookie Joel Smith may have only played 15 minutes in his debut match against St Kilda in round one, but the Demons have seen what the second-year defender can offer and have re-signed him to a new two-year deal.

As he is a rookie-listed player, the athletic defender will be permanently added to the club's primary list at the end of this season, with Smith now contracted to the Demons through until the end of 2019.

Named to debut against St Kilda, Smith dislocated his left shoulder when tackled by Saint Nick Riewoldt in the first quarter of his maiden game.

The 21-year-old had surgery on his shoulder late last month and the Demons expect Smith to be sidelined for up to four months with the injury.

"After having that little taste of things in the first round I know that I can match it at the top level," Smith told AFL.com.au.

"I'm just focusing on my shoulder now and getting it right and hopefully I can play a few games in the AFL at the backend of the season.

"It's been a lot of hard work but I'm really keen for the next few years at Melbourne and I can't thank the club enough."

Smith, the son of former Melbourne high-flyer Shaun, charged into senior contention on the back of an outstanding pre-season where he quickly catapulted up the Demons' defensive depth chart.

Injuries to Sam Frost and Colin Garland also helped put him in the frame, as Smith's athletic attributes, his aggression in the contest and speed off the mark earned him an opportunity in the JLT Community Series.

The 191cm, 87kg defender has worked closely with teammate Tom McDonald and defensive co-ordinator Jade Rawlings, who have urged him to play on instinct.

Smith's rise has occurred quickly with the former elite junior basketballer signed by Melbourne as a category B rookie at the end of 2015.

Smith represented Victoria and Australia at under-19 level in basketball before a trial with Melbourne, organised through connections with chief financial officer David Chippindall and former development coach Brett Allison, convinced him he should make the switch to footy.

"I spoke with Dad about my options and he just said, 'Do what makes you happy,'" Smith said.

"In the basketball off-season I thought about it hard and ever since I've made the move I've been rapt. There's no way I would change my decision if I had my time again."

The young defender had a solid year for Casey in the VFL in 2016, but was hampered by a groin injury as a result of not being used to the workload associated with a full-time AFL program.

Joel Smith was injured just 15 minutes into his AFL debut. Picture: AFL Photos

Melbourne football manager Josh Mahoney said Smith had quickly adopted the work habits of a professional athlete, pointing to his ability to learn as a key reason behind his fast-tracked development.

"Joel came to us as a project player but he quickly showed he had the athletic attributes required to play in the AFL," Mahoney said.

"His pre-season this year and his early JLT Community Series form was very encouraging and we saw the result of that when he was rewarded with his debut match in round one.

"We'd seen enough in Joel to know that he could develop into an AFL player and that's the reason why we've offered him a two-year deal and we're delighted he has accepted."

Joel Smith has inherited his father's trademark leap, with many regarding Shaun Smith's hanger against the Brisbane Lions at the Gabba in round 22, 1995, as one of the greatest marks of all time.

Joel, whose unsuccessful high-flying marking attempt against Carlton in the JLT Community Series would have been an undoubted highlight, is hopeful of replicating the marking feats of his Dad through his career.

"I've had a few cracks at it but haven't been able to pull one in as yet," Smith said.

"One day I'll get a good sit and hopefully take a pretty good one."