St Kilda co-captain Jarryn Geary has undergone surgery to repair the right shoulder he dislocated earlier this month.
Geary suffered what the Saints called a "serious dislocation" during the final stages of a narrow loss to Sydney at the SCG in round 12.
He required a post-match trip to hospital to have the joint put back in place after club medical staff were unable to do so at the ground.
The Saints took time to weigh up their options before Geary underwent surgery on Monday.
"Following consultation with our medical team and specialists it became obvious this was the most appropriate course of action," St Kilda chief operating officer Simon Lethlean said.
"While it's never good to have Jarryn on the sidelines, we know this won't limit his influence on the group, and that he'll provide a great example of how to tackle recovery, as he has shown time and time again."
Geary has endured a raft of injuries in recent seasons and missed the start of the 2021 campaign because of a broken leg from a training mishap in January.
The tough utility player also missed most of 2019 because of a broken leg and compartment syndrome and has played just 24 of a possible 54 games since the start of that year.
Geary, who turns 33 on Wednesday, is out of contract at the end of this season, having signed a one-year deal last September.
St Kilda take on reigning premiers Richmond on Friday night.