Collingwood is dealing with some injury concerns, but the Magpies have also been buoyed by the return of two key figures to their main training group.

Gun ruckman Brodie Grundy (toe) and star defender Jack Crisp (hip and back) showed they were over their ailments during modified match simulation at Olympic Park on Monday morning.

Grundy, who last year won All Australian honours and shared the Pies' best and fairest with Steele Sidebottom, had been sidelined for a month after new teammate Jordan Roughead accidentally stood on his little toe, which became badly bruised.

The 24-year-old resumed as though he'd never left, moving with freedom and showing no sign of the painful ailment that had restricted his mobility.

Grundy trained with his renowned intensity and athleticism, and didn't allow himself any leniency in terms of standards either, at one point loudly lamenting a kicking clanger in a keepings-off drill.

The dashing Crisp, who had post-season hip surgery and has since managed a back issue, completed part of the main session on Friday before upping his workload on Monday.

The return of this influential pair is welcome news for the Pies given the concerns over star forwards Jordan De Goey(mid-foot sprain), Will Hoskin-Elliott (knee) and defender Jeremy Howe (thigh).