GREATER Western Sydney's stirring win over Port Adelaide on Sunday has been soured by news that young defender Caleb Marchbank has been ruled out for the rest of the season.

Marchbank, who has played just two senior games this year because of an ankle injury suffered in the Giants' win over Geelong in round two, dislocated his shoulder in the NEAFL in round 16 and needs a shoulder reconstruction.

The 19-year-old consulted two separate specialists in a search for some good news over the past week, but surgery was deemed unavoidable.

"This is disappointing news for a young player like Caleb but with his long-term welfare in mind, this is the best course of action to take," Giants' head of athletic performance, David Joyce, said.

"It's been a difficult season for Caleb but we're confident he'll make a full recovery in a matter of months."

Marchbank is still not contracted to the Giants beyond 2016 and may have played his last game for the club.

GWS selected the athletic defender with pick six in the 2014 NAB AFL Draft and he is seen as a key member of coach Leon Cameron's defence, but his name has been heavily linked with a move to Carlton next year.