Geelong champion Patrick Dangerfield has had ankle surgery and will miss up to eight weeks of the AFL season.
Dangerfield decided to have an operation to fix a syndesmosis injury which he suffered in Sunday's win against North Melbourne.
While the best-case scenario is a return in four weeks, the Brownlow medallist could miss as many as eight weeks but the Cats are reluctant to put a timeframe on his return.
"It was felt the best course of action was for Dangerfield to undergo surgery," Geelong said in a statement on Wednesday night.
"Dangerfield will be out of action indefinitely with his rehabilitation and recovery from the injury determining his return to play."
Post-match Dangerfield shrugged off the injury as a "minor tweak".
Geelong medicos initially backed that prognosis before scans revealed a syndesmosis tear.
After sending the star on-baller for a second medical opinion, the Cats and Dangerfield on Wednesday weighed up whether the 31-year-old should have surgery or if he could play through the pain.
After being hurt late in the third quarter against the Kangaroos, the brilliant midfielder returned to action briefly in the last term. But he was then benched for the remainder of the match.
The fixture was Dangerfield's first since being suspended for three games for rough conduct for an incident in round one.
The Cats, in eighth spot on the ladder with three wins and two losses, host sixth-placed West Coast on Saturday.