Collingwood defender Jeremy Howe was in agony as he was stretchered off the MCG with a fractured forearm in the Magpies' pulsating 22-point AFL win over Geelong.
Howe is in hospital and coach Craig McRae said he might need surgery.
Howe had a horrifying collision with Geelong small forward Tyson Stengle in the third term of Friday night's eventful round-one clash.
After trailing by as much as 22 points in the third quarter, Collingwood roared back against the reigning premiers and won 19.11 (125) to 16.7 (103).
"He's such an important player, he's a vice-captain, we all love him," McRae said of Howe.
"So when you see one of the guys go down, one of the real good guys, that's going to be a cost somewhere."
New Collingwood captain Darcy Moore was emotional post-match as he paid tribute to his fellow defender Howe.
"It's pretty distressing and it's pretty messed up. We have to forget about it and get on with the job," Moore told the Seven Network.
Howe and Stengle contested a high ball and the Collingwood player flew into the air from the impact.
He landed heavily on his left arm and play was stopped for several minutes as he received medical attention.
Howe needed the so-called "green whistle" for some acute pain relief and the Seven Network chose not to replay the incident.
Stengle also had to leave the field from the impact of the collision, but was able to return.
The Magpies swamped Geelong with an eight-goal run from late in the third term and kicked five goals to none in the last quarter for an impressive win.
Jordan De Goey, one of Collingwood's best, put an exclamation mark on the win with a booming 50 metre shot for his third goal late in the last term.
It is Collingwood's highest score since 2018, when they made the grand final.
"I had great belief coming here tonight. I'm driving in, thinking I'm really excited for what could be, knowing we've done the work," McRae said.
The Cats edged out Collingwood by six points in last year's epic qualifying final - one of the games of the season - on the way to the premiership, and this was another classic.
Geelong vice-captain Tom Stewart was also taken out of the game at quarter-time because of a knee injury.
Fellow Cats defender Sam De Koning had to leave the field with a knee problem, but was able to return.
When Stewart and De Koning were hurt, they appeared to have trouble with their footing on the playing surface, which was re-laid after the Ed Sheeran concerts earlier this month.
"To compromise the surface is a strange decision to make voluntarily ... it was an own goal, I reckon," Geelong coach Chris Scott said post-match.
Last year's Rising Star Nick Daicos showed no early signs of second-year blues with an outstanding game for the Magpies, racking up a match-high 35 disposals.
In his first game for Geelong, former Collingwood player Ollie Henry had a night of extremes.
Magpies fans booed him incessantly, but when he kicked a goal in the second term Henry put his hands to his ears in reply.
A couple of minutes later, Henry was a bit casual as he ran into an open goal and Moore chased him down with an outstanding tackle - right in front of the Collingwood army at the Ponsford Stand end.
