St Kilda captain Jack Steele is set to be sidelined for about two months after scans confirmed he requires surgery on his injured right shoulder.
Steele hurt his AC joint after being taken down by a crunching tackle from Geelong's Jake Kolodjashnij in Saturday's 10-point win over the Cats.
Although Steele was able to play out the game, scans have since confirmed a rupture to the 26-year-old's right AC joint.
No exact timeline has been set for Steele's return, but he may not be seen at AFL level until July.
"Jack's a really tough guy and playing on last night despite his injury is evidence of that," St Kilda head of football David Rath said.
"It's really disappointing to have Jack out for an extended period of time, but it's important for him to get the treatment he needs to set him up for the second half of the season.
"He's a warrior and would continue to play if required, but we need to do what's right for Jack long-term.
"Jack's a pro on and off the field and will no doubt attack his rehab professionally, which will hopefully see him back playing as soon as possible."
St Kilda goal-sneak Jack Higgins will miss next week's clash with Adelaide after suffering a second concussion this year.
In 2019, Higgins underwent two rounds of brain surgery after he had headaches and blurred vision during games.
Saints coach Brett Ratten is confident Higgins' latest head knock is just a standard concussion.
