Brumbies No.1 Blake Schoupp appeared to have dislocated his shoulder in the first two minutes of his return from an injury to the same shoulder in Perth on Saturday night.
He now looks unlikely to appear in his side's quarter-final next Saturday, as does veteran prop James Slipper, who is battling an upper calf injury.
It put a dampener on an otherwise positive night for the Canberrans, who go into the finals with positive momentum, albeit disappointed they were unable to turn their most successful Super Rugby regular season in two decades into a top-two finish.
Both sides went into the match knowing they could do nothing to improve their ladder position, after the Melbourne Rebels' loss to the Fijian Drua ended the Force's finals hopes, while victories to the Blues and the Hurricanes consigned the Brumbies to third place.
But there was no chance Brumbies coach Stephen Larkham was going to let his men go into the match without their collective foot firmly on the pedal.
Captain Allan Alaalatoa opened the scoring with a try in the sixth minute, before speedster Connor Toole doubled the lead with his eighth try of the season, outpacing his opposite number to run on to a perfectly placed Tom Wright kick.
The Force heaped pressure on the Brumbies for long passages of the game, but were all too often the architects of their own demise.
The visitors were solid in defence, but the Force were guilty of making simple errors in attacking positions to let their opponents off the hook.
They were let back into the game when Brumbies halfback Ryan Longeran was shown a soft yellow card shortly after the half-hour for interfering in a ruck. The Force immediately capitalised with a try through flanker Carlo Tizzano.
Force fullback Curtley Beale looked to have clawed back another try for his side right on the stroke of halftime, but was disallowed after the sideline referee spotted a forward pass in the build-up.
The Brumbies continued to defend solidly in the second half and were more clinical in attack when given the opportunity to break forward.
Back-rower Luke Reimer impressed again off the bench, forcing key turnovers with his intensity in the ruck when the Force threatened the Brumbies' tryline.
Toole's pace once again came to the fore, sprinting back to make a try-saving tackle on Issak Fines-Leleiwasa when he had only green grass in front of him a few yards out from the line.
After a turnover from a Force lineout in their own 22m zone, Toole then broke clear and drew two defenders to put fullback Wright through for a try of his own.
The Brumbies took the heat out of the game in the final quarter of the match.
The Force scored consolation tries through Fines-Leleiwasa and George Poolman in the final minutes, but by that point both teams were no longer competing with all their heart.
Larkham rested several key men as the game petered out, including five-eighth Noah Lolesio and Alaalatoa, as he cast his gaze towards his side's home quarter-final in a week's time.
The Brumbies will be eagerly tending to their wounded before they host the Highlanders at GIO Stadium after triumphing over the New Zealanders 27-21 in Dunedin in March.
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