Cameron will undergo surgery to repair the AC joint in his left shoulder this week, and will miss at least four of the six remaining home-and-away rounds.
The 33-year-old was taken to hospital in Sydney after a brutal collision with GWS opponent Clayton Oliver in the final quarter of the Cats' 13-point loss at Engie Stadium.
Ninth-placed Geelong (9-8) are hopeful Cameron will miss six weeks at worst, as they aim to return to the top six.
Cameron was just one player hurt on a night of carnage for the Cats and Giants.
Jack Henry (throat) and Tanner Bruhn (neck) were also taken to hospital, but have been cleared of serious injury, while GWS youngster Phoenix Gothard dislocated his left shoulder.
The Geelong duo will be monitored during the week to assess their return-to-play timeline.
Already managing lingering soreness from a healed right arm fracture, Cameron had starred as a surprise defender against the Giants before his latest injury.
"I'm led to believe that it's sort of a four-to-six-week return to play period, which leaves us optimistic," Cats coach Chris Scott told Kayo Sports on Monday night.
"We'd like to think that's our default position on these things, and he certainly is.Â
"So, he has an issue with his arm as well that will be looked at at some point ... but it's been decided.
"It was pretty clear that it (his arm) can wait until the end of the year, so we're hopeful that if the team's good enough we'll get him back at a hopefully important part of the season."
Elsewhere, Hawthorn defender Karl Amon has undergone knee surgery in a bid to be fully fit and firing for the finals.
After managing the pain throughout the season, the third-placed Hawks (11-5) have opted to send Amon for a clean-up procedure following the club's 64-point win over Carlton on Saturday.
The 30-year-old Amon has battled knee issues throughout his 13-year career, and missed this year's Easter Monday fixture against Geelong in round four due to cartilage irritation.
Amon had just returned to the side to help the Hawks snap Carlton's seven-game winning streak after being managed against Melbourne the week prior.
He had 12 disposals, one mark and two tackles in the thumping win over the hot Blues in the rain at the MCG.
"This has been in consideration for a number of weeks," Hawks football boss Rob McCartney said in a statement.
"While Karl has had some intermittent pain throughout the season, there was no further risk in him playing games.
"We expect Karl to be available for selection before finals."
Hathorn are hoping to regain crafty small forward Nick Watson (hamstring) against Richmond, while defender Josh Battle may have a chance to play after having his appendix removed a fortnight ago.
Collingwood are hopeful small forward Lachie Schutlz is a "short-term" prospect with his low-grade ankle syndesmosis injury.
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