Briggs was seen training apart from teammates on Thursday ahead of Saturday's match at the Gabba, with coach Adam Kingsley confirming the ruckman was struggling.
"Briggsy is managing some shoulder stuff so he's probably unlikely this week at this point in time," Kingsley said on Thursday morning, just hours his omission was confirmed with the release of the Giants' team.
Kingsley expects Briggs to miss just one game.
Kieren Briggs is grounded during the Giants' dramatic last-out win over Hawthorn. (Lukas Coch/AAP PHOTOS)
Key forward and backup ruckman Lachlan Keeffe will slot in for Briggs, with Braydon Preuss out for the season with a back injury.
It will be Keeffe's first AFL match this season after playing 14 games last year.
The 34-year-old will do battle with Brisbane's Oscar McInerney, who is fifth in the league for hitouts (617) after his 36 in their 85-point win against St Kilda last round.
Lachlan Keeffe comes into the Giants team for his first AFL game of the season. (James Ross/AAP PHOTOS)
"We've had a few injuries with our ruck stocks so it feels like Keeffe is the next man in and he's more than capable," Kingsley said.
"He played in the ruck last week at VFL level and did quite well so he's one of these guys that adapts pretty quickly.
"We're pretty comfortable that he can mix it with a really good ruckman up there in McInerney.
"There'll be times where Lachie has good moments. There'll be times where McInerney has good moments.
"That's the nature of good players going at it."
Stephen Coniglio (shoulder) will miss another match, but Josh Kelly returns from a calf injury.
The Lions will again be without Eric Hipwood (groin), but Darragh Joyce is back from a broken jaw.