Isaac Heeney will be out of action for at least a month, meaning his AFL Rising Star hopes have taken a big hit.
The 19-year-old's knee injury was one major disappointment for the Swans in the wake of the 38-point win over Melbourne on Saturday night at the MCG.
Heeney landed heavily in the second term and hurt the posterior cruciate ligament in his right knee.
The good news for Heeney and Sydney is that he did not suffer a season-ending anterior cruciate ligament rupture.
"He's landed awkwardly and it's a PCL injury," Swans football manager Tom Harley told Channel Seven's Game Day.
"It's not an ACL, which is important, but it's still really early to diagnose.
"(He's) looking at four to six weeks."
Heeney had impressed so far in his debut season and was the round-three Rising Star nominee.
The Swans academy graduate had been the Rising Star favourite for this season.
He also missed last week's narrow loss to the Western Bulldogs with an ankle injury.
