SYDNEY could be without co-captain Josh Kennedy for an extended period after the tough midfielder suffered a knee injury in Friday night's loss to Collingwood.

Kennedy damaged his medial ligament during the third quarter of the Swans' seven-point defeat at the SCG and spent the remainder of the game on the bench.

The veteran had been influential for the home side with 22 possessions, five clearances and four tackles until he was forced from the field.

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After the match Swans coach John Longmire said he isn't expecting positive news from scans on Kennedy's knee in the coming days.

"We'll have to wait and see, but it'll definitely be a few weeks I'd say," he said.

The loss of Kennedy and fellow midfielder George Hewett (head knock) during the third term made it tough for the Swans, who led the Magpies by eight points at the last change.

Collingwood had their own worries with Daniel Wells also playing no further part in the game when he injured his knee during the third quarter.

Longmire said despite the disappointment of the loss he was proud of his young team's efforts to push one of this year's premiership fancies.

"Sometimes you lose a game but you don't go backwards, and that’s probably how I feel," he said.

"They're a fantastic team that made last year's Grand Final, they'd won six in a row, and we had a real go.

"I still reckon we took a step forward."

The return to form of athletic forward Sam Reid was one of the biggest positives to take out of the Swans' defeat, with his six goals almost dragging his side over the line.

Reid, who has battled persistent issues with his body in recent years, took nine marks, six of those contested, and was a constant threat for the Pies.

"He was fantastic and that’s as good a game as I've seen Sam play," Longmire said.

"Our forwards were able to identify that he was on the go and give him plenty of opportunities, and he certainly responded.

"He's missed two of the last three years (with injury) and you take a bit to get going when you miss footy like that, but he's got a plan and he's working towards it."

The Swans are in a mood tonight, they've slotted the first three! #AFLSwansPies pic.twitter.com/YNyr8z2gFt — AFL (@AFL) May 24, 2019

The return of Lance Franklin was a huge help to Reid, who was able to capitalise on his size advantage opposed to Jeremy Howe and Jack Madgen, with Jordan Roughead given the task on Franklin.

Longmire couldn't resist a crack at some media reports during the week that urged him to play Franklin further up the ground to decrease his side's dependency on the four-time Coleman medallist.

"(The media told us) we had to have him on the wing before the game," he said with a laugh.

"Maybe 'Reidy' wouldn't have kicked six (if we'd done that).

"It's all swings and roundabouts, it's an opinion business."

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