Jarrad McVeigh will be racing the clock to return for the AFL finals, with Sydney expecting the veteran to be sidelined for six weeks because of a broken collarbone.
McVeigh, Dan Hannebery and Kieren Jack all suffered injuries in the Swans' loss to Geelong on Thursday night.
Hannebery is set to be out for at least three weeks, with scans confirming a calf strain, while Jack's knee problem is better than first feared.
Jack has a grade-one medial strain, which coupled with a 10-day break means he is a chance to face North Melbourne next week.
McVeigh was hastily booked in for surgery on Friday, with the club wanting the 33-year-old to start rehab as quickly as possible after hurting himself tackling Quinton Narkle at the SCG.
The Swans have seven games remaining in the regular season, leaving McVeigh little time to regain match fitness before September.
Any kind of setback could potentially mean the end of McVeigh's career, but that is a scenario that both player and club won't contemplate.
"He will have a plate inserted, recover from the surgery and rehab accordingly," Swans football manager Tom Harley said.
"It is always difficult this far out to put a hard and fast prognosis on it, but we will say six weeks."
The absence of McVeigh, Hannebery and Jack would rob Sydney of some 761 games worth of experience.
Hannebery and Jack have both struggled at times this year, but McVeigh has wound the clock back and been one of the Swans' most consistent performers.
McVeigh's form has prompted some to speculate he could play on in 2019, extending a career that started with the 2002 draft.
Harley noted the Swans will take a cautious approach to Hannebery's setback.
"He had a similar one in pre-season," Harley said.
"We are certainly not going to rush him back, we will give him every opportunity to get himself fully fit.
"We will let the injury recover and then put at least another week on top of that."
Jack, who finished Thursday night on crutches, will be assessed next week.
"Given the ten-day break before the North Melbourne game, we will give him every opportunity (to play)," Harley said.
Swans defender Lewis Melican, who was close to returning from a recurring hamstring injury that has kept him on the sidelines for three months, has suffered a fresh setback and will now target a return late in the season.
The news is better for Sam Reid (quad), Tom Papley (hip) and Isaac Heeney (concussion), who could all return against the Kangaroos.