HE'S THE low-profile young Swan earmarked for a crucial role this year and beyond.

One-time rookie Lewis Melican burst onto the scene two seasons ago, catching the eye in just his 12th game when he kept St Kilda champion Nick Riewoldt to one goal to earn a NAB AFL Rising Star nomination.

The fact coach John Longmire and co. were so willing to entrust the 195cm defender with such a big job as a lightly played 20-year-old spoke volumes.

Among Melican's other individual tasks that season were James Sicily – then playing as a forward – Mitch McGovern and Charlie Curnow, as the Swan racked up the first 17 games of his AFL career.

It was a somewhat belated rise after a cracked pelvis ruined his 2015 season, then a broken thumb and separate right hamstring tears interrupted his following campaign.

Melican, now 22, sustained two more hamstring injuries on his left leg last year and wasn't sighted after round three, but is primed to regain his spot down back for Sydney.

He is Heath Grundy's long-term successor and will also release Dane Rampe on occasion to play on small and medium types, rather than the Sydney co-captain fighting out of his weight division so often.

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"Lewis will come into the team and allow others to do other things," Longmire told AFL.com.au.

"We need Lewis to play … and we're confident in what he can deliver for our team when he's playing and up and ready and fit, because we have huge faith in him to be able to deliver that.

"But we need to make sure he gets through a pre-season and gets into the start of the season and picks up the game again, because he hasn't trained much, let alone played, during that period (out)."

Grundy and Nick Smith, who was restricted by a hamstring injury earlier in the pre-season, continue to be defensive pillars despite preparing to turn 33 and 31, respectively, in June.

However, Aliir Aliir's re-emergence last year and Melican's return will give Longmire more flexibility.

"We'll pick the best team that's available at that point in time and if they're all fit, what a wonderful challenge to have," the coach said.

"We're confident with those boys and what we'd like to do is make sure Dane Rampe's not playing on the keys every week. We think that's an evolution of our team as well.

"As good as he is on the talls, we think he's more than capable on those small forwards that are around and those changing midfielders out of the goalsquare."

Grundy signed a fresh one-year deal in August and has had "a very good" pre-season so far and was feeling "great", according to Longmire, after taking some time out for mental health reasons last year.

"He had the birth of his second child last year and the baby wasn't sleeping and it's really tough," Longmire said.

"When you don't have family support, people don't understand how much of a challenge that can be.

"If you're not getting any sleep and you're trying to perform, it's not like you're going to work being an accountant or a solicitor. You've got to go out and run and exert yourself physically.

"I won't go into the details of (Grundy's situation), but you've got to respect what it is and, most importantly, allow the player to get himself right."