Brisbane will be without Callum Ah Chee and Marcus Adams for a second successive week due to separate head knocks, with the pair unable to be cleared through the AFL's concussion protocols ahead of Round 23.

Adams suffered both rib and head injuries in the Lions' Round 21 match against Carlton, with concussion symptoms arising after the match.

Ah Chee suffered concussion in a collision with Blues captain Patrick Cripps in the same match, joining Adams in missing Brisbane's Round 22 clash with St Kilda.

The duo will again remain sidelined due to their respective ailments, a twin blow for Brisbane ahead of their finals-influencing clash with Melbourne on Friday night.

A loss to the reigning premiers could see the Lions fall from their current position in the top four to as low as sixth spot.

A win could see Brisbane rise to second spot, securing a home qualifying final in what would ve a major boost for their premiership credentials.

The absences for both Ah Chee and Adams will likely mean Jack Payne and Jaxon Prior could retain their spots in Chris Fagan's side for Round 23, while veteran Mitch Robinson remains in the frame after being managed.

BRISBANE, AUSTRALIA - FEBRUARY 26: Marcus Adams handballs during a Brisbane Lions joint AFLW & AFL Media Opportunity at Giffin Park on February 26, 2019 in Brisbane, Australia. (Photo by Chris Hyde/Getty Images)

Brisbane have also confirmed that young forward Blake Coleman will join Ah Chee and Adams in concussion protocols, having suffered a worrying head knock in a collision with teammate Kalin Lane in the VFL over the weekend.

Meanwhile, duo Carter Michael and Tom Berry have taken the next steps in their recoveries from shoulder surgery.

The Lions will host the Demons at the Gabba at 7:50pm (AEST) on Friday night.