Gosiewski left the field late in the Broncos' hapless 32-4 loss to Manly at Brookvale on Saturday night, and it is understood his head knock was ruled as a category one.
It means the Broncos forward will enter the NRL's concussion protocols, ruling him out of Magic Round and Brisbane's heavyweight clash with the Warriors.
The Broncos will get halfback Adam Reynolds back for that match, but the defending premiers are desperately short on troops.
Gosiewski joins fellow forwards Payne Haas, Corey Jensen, Brendan Piakura, Blake Mozer and Billy Walters on the sidelines.
Prop Ben Te Kura is also still unavailable while attending a six-week NFL training camp in the USA.
None of that group are expected to return next week, while Brisbane are also still without suspended centre Kotoni Staggs along with injured backs Grant Anderson, Delouise Hoeter and Deine Mariner.
Saturday night's flogging at the hands of Manly was easily the Broncos' worst performance of the year, after having been gutsy without several stars in recent weeks.
They routinely handed the ball over, completed at less than 50 per cent in the second half and cost themselves good field position.
The tone was set by the gaping hole left open for Manly's first try through Joey Walsh, while Brisbane's attack managed just one linebreak in the 80 minutes.
Afterwards, coach Michael Maguire would not cop the side's injury toll as an excuse for the defeat, which has left them 11th on the ladder.
"That's not an excuse," Maguire said.
"We missed the mark. It's as simple as that.
"You go back a couple of weeks ago and people talked about the people we didn't have.Â
"Well, we were able to perform in Campbelltown against the Tigers and then against Canterbury. That's the expectation that the players have."
Meanwhile, Manly are set to lose Brandon Wakeham for their Magic Round clash with Wests Tigers after he was sent to the sin-bin late in the first half.
The hooker is facing a one-match ban after being charged for a high shot on Brisbane prop Ben Talty, or two games if he fights the charge and loses at the judiciary.
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