After a surprise cameo in defence, Cameron hurt his left collarbone in a heavy fourth-quarter collision with Giants star Clayton Oliver as the hosts secured a 12.14 (86) to 11.7 (73) victory at Engie Stadium on Saturday.
GWS trailed by a game-high 39 points in the third quarter before slamming through six unanswered goals, with Callum Brown kicking the decisive major.
Leading all afternoon until Brown's goal, the Cats were hanging by a thread after Cameron, Tanner Bruhn and Jack Henry went down with injuries.
Geelong defender Henry was forced off in the second term after a knock to the throat, before a heavy third-quarter tackle from Giants midfielder Toby Bedford left Bruhn with a neck concern.
The Cats had already brought in Mitch Knevitt as a last-minute replacement for Mark O'Connor.
Geelong coach Chris Scott said Cameron, Bruhn and Henry would remain in Sydney.
"They're getting checked medically," Scott said.
"You can catastrophise these things. I don't think we should. I think we should just wait to see what the diagnosis is.
"(Losing three players) was obviously a challenging situation. I didn't think it was insurmountable, but we just weren't quite good enough in the end."
GWS (8-9) remain in the hunt for finals and sit 11th, while the Cats (9-8) are eighth.
"Very pleased with the way that we played in the second half. Our fight, our ability to be resilient, never surrender as we talk about," Giants coach Adam Kingsley said.
"We're capable. Clearly, consistency again today was a little bit of an issue.
"First half versus second half looked quite different, and so that's our challenge. If we produce like the second half, which I know we're capable of ... then we're a really, really good team in my view."
Cameron, still suffering the effects of a broken arm from last year's grand final, had impressed in defence, taking 11 marks after starting in a match-up with former GWS teammate and good friend Toby Greene.
The two-time Coleman Medal winner was stationed at a half-back after his self-labelled "borderline pathetic" outing against the Brisbane Lions in the previous round.
Young gun Ollie Dempsey (three goals) and Shaun Mannagh (four) took attacking duties in Cameron's absence.
At the other end, Giants key defender Sam Taylor rediscovered his dangerous best in the sixth game back from a serious hamstring injury he suffered in this year's State of Origin match.
The All-Australian finished with 11 intercept possessions and nine marks, while Clayton Oliver (36 disposals, nine clearances) was crucial at the contest.
Riley Hamilton - in just his second AFL game - kicked two crucial majors in the second half to keep GWS in the game.
The Giants were under siege early and trailed by 18 points at the first break, with Geelong notching 23 forward entries to the home side's nine.
GWS were able to regain territory and win clearances 25-22 in the second quarter, but had no scoreboard reward for effort and trailed by 25 points at the main break.
As the Cats' ascendancy continued, Mannagh provided a brilliant highlight when he kicked his third goal despite being "pantsed" by Giants midfielder Ryan Angwin.
GWS forward Jake Stringer, last week's hero with a career-best seven goals, then hit the scoreboard with his only major near the end of the third term to kickstart the Giants' comeback.
6°C