FORMER first-round pick Harry DeMattia is currently in the League's concussion protocols, stalling an impressive second pre-season at Collingwood.

The 19-year-old had been building a case across the summer to be considered for an early season debut, after playing 13 VFL games in his first year at the Pies.

But the setback could impact his chances of impressing in the match simulation against Gold Coast and Brisbane next week ahead of the AAMI Community Series clash against Richmond on February 26.

DeMattia had his first pre-season derailed this time last year when he underwent finger surgery following an incident at training, which sidelined him for 10 weeks.

The former Dandenong Stingrays and Vic Country captain signed a two-year contract in December to extend his time at the Magpies through to the end of 2027.

DeMattia has been eyeing a spot at half-back or on a wing in Craig McRae's best 23, but rebounding spots are highly sought after at Collingwood, even after the departure of John Noble to Gold Coast.

All-Australian wingman Josh Daicos has been training at half-back across the summer alongside prized recruit Dan Houston, who is also set to spend time in the midfield.

Wil Parker and Oleg Markov are also fighting for opportunities in a defence that already includes Brayden Maynard and Isaac Quaynor. Free agent signing Harry Perryman is expected to spend time playing at half-back but has trained mainly as a midfielder since arriving from Greater Western Sydney in October.

Premiership player Patrick Lipinski has spent the pre-season playing on a wing opposite veteran Steele Sidebottom, while versatile veteran Will Hoskin-Elliott is another option for Collingwood on the outside.

Star midfielder Jordan De Goey was back running on Monday after dealing with bone bruising in his knee from a recent knock late last month.

The 28-year-old trained predominantly with injured Brownlow Medallist Tom Mitchell, while also completing a few drills with the main group.

De Goey is not a lock to face GWS in Opening Round and won't be rushed after being limited to just 13 appearances in 2024 due to chronic groin injuries before a high-grade hamstring injury ended his season, leading to a trip to Doha to visit leading sports medicine clinic Aspetar.

Mitchell hasn't played since Anzac Day and only managed six appearances in 2024 due to a lingering foot injury that flared again in December. But the Brownlow winner proved in 2023 how valuable he can be, finishing fourth in the Copeland Trophy after playing all 26 games in the premiership campaign.

Beau McCreery and Fin Macrae are also on modified programs after recent niggles, but spent enough time training with the main group on Monday to indicate they will play some minutes next week or against Richmond on February 26.

While Houston and Perryman have drawn most of the attention since moving clubs last October, delisted free agent signing Tim Membrey has built a case all summer to be picked in the 23 against the Giants.

The former St Kilda and Sydney spearhead has slotted in seamlessly alongside Dan McStay and Brody Mihocek, offering a mobile target in attack at 190cm.

Membrey kicked 30.9 from 19 appearances in his final season at Moorabbin but wasn't offered a new deal, before the Magpies swooped in November, signing the Victorian on a two-year contract.

Reef McInnes looms as the other change to Collingwood's best 23 after starring in defence across the summer, following a positional switch at VFL level last year.

The 22-year-old was drafted late in the first-round in 2020 as a big-bodied midfielder, but spent most of his first four years at the Magpies playing in attack.

Collingwood will head to the Gold Coast early next week ahead of the clash against the Suns and Lions next Thursday night.