SYDNEY coach John Longmire has heaped praise on Luke Parker after the veteran returned alongside captain Callum Mills for the 79-point thumping of North Melbourne at the SCG on Saturday.

But while Parker and Mills bolstered the midfield in their first matches of the season, the Swans will be sweating on the fitness of Justin McInerney after the winger was subbed out with a knee injury.

Parker was a late inclusion and started as the substitute but gathered 13 disposals and booted two goals once called into action during the third term.

Teammates swarmed the three-time club champion after he kicked his first goal – also his 200th for the Swans – and repeated the response when Mills added a major in the final term.

SWANS v KANGAROOS Full match coverage and stats

Parker had found it hard to find a spot in a rampaging Swans midfield after breaking an arm in a pre-season hit out, then was banned for six matches for a high bump while forced to comeback through the VFL.

“He did such a great body of work whilst he's been out suspended. He worked as hard as any player I've ever seen through that period and did it all off his own back,” Longmire said.

“He worked so hard and had great confidence to come back in and make an impact.

“He made the call that he wanted to get back in amongst it, and to his great credit he was super, fantastic.”

Sydney will welcome back the suspended Isaac Heeney next week for the mouth-watering clash with Brisbane but look set to be without McInerney.

The hard-running midfielder copped a knock to the knee while contesting the ball then looked in obvious discomfort soon after while standing the mark soon after.

The 23-year-old has not missed a match this season while averaging a career-high 20.2 disposals but could be heading for a stint on the sidelines.

"It was unusual. It didn't look as though there was a lot in it, just looked like his leg collapsed a little bit," Longmire said.

"We'll have to wait and see, the early diagnosis is a PCL.

"I'm not sure what that means, he'll go into a brace in the short-term and just see what happens from there."

The Kangaroos had impressed in recent weeks with two wins and three narrow defeats but after staying with the Swans through the first term were outclassed as the ladder-leaders put the foot down.

An emerging midfield battled hard around the stoppages, with the Swans only winning clearances 38-34, but the Roos were no match once the ball was on the outside as they lost the inside-50 count 64-39.

"It's all experience for these young players, we've got (Harry) Sheezel, (George) Wardlaw and (Tom) Powell and these guys that are just building their resume in terms of exposure to senior AFL footy,” Kangaroos coach Alastair Clarkson said.

"(Tristan) Xerri the ruck playing against (Brodie) Grundy; Grundy's played 200 games, Xerri has played 50.

"The exposure that they get to these types of contests, you just wish improvement and growth as a footy club is all linear, but you have your ups and downs. We've been pretty good for the last month and a bit but we well and truly lowered our colours today.”