Ross Lyon has declared it is time for Fremantle to "double down" on its rebuild and promote more youth after watching the Dockers suffer their first loss at Optus Stadium against a travelling side.

Freo was in Sunday's contest against North Melbourne until midway through the final term, only trailing by three points when Michael Walters soccered his second goal.

But the Roos put the foot down and ran out 28-point winners, leaving the Dockers' season teetering at 4-6.

Fremantle picked five players aged over 30 on Sunday – Aaron Sandilands, David Mundy, Michael Johnson, Hayden Ballantyne and Danyle Pearce – but Lyon indicated youth will get more chances in the back half of the season.

"We're going to double down on what we're doing. It was tough this week to leave (Mitch) Crowden out, but he needed a bit of freedom, we've got Taylin Duman who needs to play," Lyon said.

"Griffin Logue played his first game back (from a foot injury at Peel), we'll bring him back as quick as we can.

"We'll look to bring (Stefan Giro) in. At the minute, there's not a lot of youth down there (at Peel), to be honest.

"They're either in rehab, like Sean Darcy (knee) and Hughie Dixon (ankle) and Brad Hill's (knee) there, Harley Bennell played his second game midfield.

"We saw the quality and his run. We're going to double down on that and as soon as those young players are available you'll see more of it, because that's what we need to do.

"I think it's been balance but we'll probably skew it to a little bit unbalanced to just keep the youth in and keep them going.

"Regardless of anything else around that, that needs to happen for the future of this club and we're fully committed to that.

"Regardless of any criticism or observations it's the right thing to do and we feel we're doing it.

"But you can only play the ones you've got."

Bennell had 16 disposals and booted a goal for the Thunder on Saturday in a classy performance despite wet and windy conditions.

The former Sun has only managed two games for Freo in two and a half years but is close to his next comeback from repeated calf issues.

"If he keeps progressing like this we know we're going to have a really good player. He just needs a bit of luck with his body," Lyon said.

"If he keeps playing his part, we'll keep playing ours and hopefully in the end we're all vindicated.

"We've got a special player at the club, but there's plenty of hurdles to jump. But he's well on the way."

Lyon lamented ill-discipline – evident in several 50m penalties – a lack of hardness before half-time and not enough polish for Sunday's loss to the Roos.

North's twin towers Jarrad Waite (three goals) and Ben Brown (two) also proved to be a thorn in Freo's side on a difficult day for forwards.

"On Alex Pearce, a quality defender, (Waite) just did a couple of things that separated it a little bit," Lyon said.

"I thought as the game was really tight their key forwards took some clunks and kicked the goals."

Lyon refused to blame a non-decision when Joel Hamling appeared to be wrestled away from the ball in the final term, allowing Shaun Atley to kick a crucial goal, for Freo's defeat.

The Freo Dockers were only three points down and had momentum after two quick goals.

"There's lots of moments in a game, you get plenty of moments to get it right, that's just one moment," Lyon said of the Hamling incident.

"You want to be in positions where one or two of those moments doesn't affect you.

"That's flip of the coin stuff."