Adams was subbed off with a rib injury earlier this month against Carlton and experienced concussion symptoms in the days that followed.
The big-bodied, in-form defender has been unable to shake those effects, and coach Chris Fagan on Monday conceded his season "looks to be done" ahead of Thursday's elimination final against Richmond.
Hard-nosed defender Noah Answerth and livewire Cam Rayner are suspended for the clash, while Dayne Zorko will play after a tumultuous fortnight since his sledge of Melbourne's Harrison Petty triggered calls for him to step down as captain.
Darcy Wilmot, Brisbane's top pick in last year's draft, has a chance to debut after the 18-year-old was left out of the Lions' VFL side that played on Saturday.
Defender Daniel Rich confirmed Adams had only made occasional visits to the club as he battled serious concussion symptoms but was confident the void could be filled.
"It's not like we've played the same seven defenders every week ... hopefully that's prepared us for what's to come," Rich told reporters on Monday.
"He's (Wilmot) the kind of guy that would love it, thrive off that and I'd love to play alongside him. He's a really exciting prospect."
Former Western Bulldogs talent Adams, contracted until next year at the Lions, played no more than 11 games in a season between 2016 and 2020.
But he featured 17 times last year and showed some of his best form in 18 starts this year in tandem with fellow key defender Harris Andrews.
His absence will create more headaches for the Lions against a Tigers attack that's kicked 100-plus totals in their last four games, and which is set to welcome back champion midfielder Dustin Martin.
The 2017 Brownlow Medallist can be expected to swarm with the Tigers' other potent small forwards, while in-form talls Tom Lynch and Jack Riewoldt present an imposing number of options to goal.
It's all extra noise around Brisbane, a dominant regular-season team who have gone 1-5 over the past three finals campaigns.
Referring to the Zorko incident, Fagan told SEN: "It's a difficult one and a distraction you could do without, that's for sure.
"It was an interesting one; what he said was inappropriate and he did apologise, which he didn't need to be prompted on.
"On the footy field it's a bit of a two-way street ... there was a lot come his way that didn't really get reported."
Fagan said the Lions were planning to face Martin, who's been sidelined by a groin injury since round 16.
"It's hard to know ... you've just got to expert the best version of him and play him to that," Fagan said.
"It's a long time out of the game but he's a champion player and if he plays, no doubt he'll rise to the occasion."
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