DOUBT surrounds several key Collingwood players ahead of Saturday's clash with Sydney at the SCG, but defender Tyson Goldsack is on the brink of a remarkable recovery from a knee reconstruction.

Wingman Chris Mayne, who has played every match since round six, headed for scans on Tuesday, missing training with teammates.

While Mayne remains confident he'll be right to tackle the Swans, his fitness is one of a number of concerns for Nathan Buckley ahead of the trip north.

Forward Brody Mihocek walked laps on Tuesday, still nursing an ankle complaint he suffered in Saturday's loss to Richmond, and the Pies believe he could face the Swans.

The mature-age recruit underwent scans on Sunday, playing out Saturday's loss to Richmond as the Pies were reduced to two on the bench with injuries to Matt Scharenberg and Jeremy Howe.

While Scharenberg has been ruled out for the season with his third ACL, Howe joined teammates on the training track on light duties.

After assisting with training drills, Howe will look to ramp up his efforts during Thursday's main session to prove he's over his concussion symptoms in time to face the Swans.

Goldsack completed the session as he edges closer to a VFL return – possibly as soon as this week – after rupturing his ACL in pre-season.

"As long as we get final boxes ticked at the end of the week from our medicos and specialists, we are looking for Tyson to resume in the VFL this week, which is great news," Pies football manager Geoff Walsh told collingwoodfc.com.au.

"It's a really quick recovery. Barring any last-minute changes of heart or mind from our medical staff, we expect him to get clearance later this week."

Veteran Ben Reid joined teammates in competitive training as he eyes a return through the VFL next week, having not played in the AFL since round 10 due to calf and knee setbacks.

"Since he had the scrape on both knees, he has stepped up his running and we would expect Ben to join in full training this week and do some full training again next week," Walsh said.

"Hopefully, in 10 days' time, we're looking at Ben being available for selection which is a really strong recovery from his operation."

Adam Treloar completed running alongside injured teammate Flynn Appleby as he pushes his case for a late season return.

Treloar, who underwent surgery to repair an injured hamstring tendon in June, ran at close to full pace under the watchful eye of Pies' fitness staff.

James Aish and Alex Fasolo, who have both featured in the VFL in the past fortnight, trained strongly.