Forward Eric Hipwood will get scans on his injured right knee on Tuesday afternoon but is in extreme doubt to face Port Adelaide on Sunday.
Hipwood suffered the injury in the opening quarter of Brisbane's head-turning 20-point victory over Greater Western Sydney and battled the game out under duress.
At Lions' training on Tuesday morning he was sporting a huge brace on the knee and was limited to handball drills, with coach Chris Fagan confirming scans were still to come.
"We won't be taking any risks with him," Fagan said.
"If he's not right, he'll have a rest.
"We're pretty sure whatever the outcome is, if he is out, he won't be out too long."
Hipwood was arguably the game-winner when Brisbane over-ran Port in its 17-point round three win, kicking a career-high six goals, including five in the first half.
The 21-year-old has had a strong season, kicking 26 goals, and would be a significant loss.
"The fact he was able to play out the game gives him a little bit of confidence," Fagan said.
"He had a bit of trouble on change of direction, but straight-line running and his ability to jump, he wasn't impeded."
Hipwood's troubles have been offset by the return of ruckman Oscar McInerney, who missed the Giants match following concussion the previous week.
Fagan said McInerney was passed fit to play at the weekend, but Brisbane decided to take a conservative approach.
"My experience with guys that get concussions, a lot of them pass the test but they don't always play all that well, because their reflexes aren't so good or their confidence is down," Fagan said.
"We just wanted to make sure he was OK."
Sunday's match at Adelaide Oval pits not only two top-eight teams against one another, but two of the most attacking and daring teams in the competition.
"It will be interesting to see whether it becomes a game of high scoring or a war of attrition, I'm not sure which way it will go," Fagan said.
"I'm sure neither of us coaches will care what the score is at the end, or how many points we've kicked, as long as we've got the W."
