Sydney backline stalwart Nick Smith recognises it's going to be tough for his part of the team to hang onto all their young guns this season.

One key factor in Sydney's surge to the minor premiership and Grand Final in 2016 was the successful integration into the defence of several young players.

Callum Mills, Aliir Aliir and Harrison Marsh were all blooded at the back and the Swans didn't miss a beat.

They conceded the fewest points during the home and away season, giving up an average of just under 67 points a game.

The rebounding side of Sydney's defence also benefited from an infusion of youth, with Jake Lloyd and Zak Jones adding dash.

"It's almost strange how quickly those guys assimilated into the backline and we felt pretty at ease playing with each other last year," Smith said.

However, the backline won't have exclusive access to all those players this season.

Jones got plenty of midfield minutes in the pre-season, Lloyd could spend time on the wing and Rising Star winner Mills, who excelled in an unfamiliar half-back role, is likely to get some time in midfield, the area for which he was recruited.

"That's the trouble, trying to keep them (in the backline)," Smith said.

"I'm not sure what the plan is but you'd think long-term 'Millsy' will probably play in the midfield, probably 'Lloydy' on a wing."

Even if some of those players do get sucked into Sydney's deep midfield rotation, a new wave of defenders is ready to step up.

Among the hopefuls are 2016 NEAFL team of the year and Grand Final best on ground winner Nic Newman, teenage draft pick Jack Maibaum and the rookie listed Lewis Melican.

"We've got those guys ready to come in, when they get an opportunity, we think they are ready," Smith said.

"In the last couple of years, guys have had to do a lot of groundwork in the twos and get in good habits, so when they do get picked they are ready to go."