GREATER Western Sydney's long-running injury woes have continued before the new season has even begun, with star forward Toby Greene to have surgery on Thursday to repair an ankle issue.

Greene suffered the injury in the Giants' semi-final loss to Collingwood at the MCG, and while the club's medical staff had hoped to avoid an operation, the problem hasn't improved over the off-season.

The gun forward went goalless from just nine possessions against the Pies and was well beaten by Brayden Maynard, after booting three goals and gathering 27 touches against Sydney in the Giants' win over the Swans in their elimination final the previous week.

FULL FIXTURE Every round, every game

It's a cruel blow for the Giants, who have struggled with injury problems to star players over the past three seasons.

The 25-year-old is expected to be back running and into full training following the Christmas break, but his recent history isn't great coming off a limited preparation.

WHO MAKES FINALS? Do the 2019 Ladder Predictor

Greene missed most of last pre-season after breaking his toe while on an overseas holiday, and after making it back for the opening round of the year, he played just nine games for the year because of hamstring and foot problems.

The 2016 club champion and All Australian is arguably the Giants' most important player and he was sorely missed inside 50 this year, especially in the absence of Jeremy Cameron (suspension) and Jon Patton (knee) for large chunks of the season.

TOUGHEST DRAW? Champion Data ranks every club

GWS head of athletic performance David Joyce said an operation gives Greene the best chance to be physically ready for the beginning of the 2019 home and away season.

"It's unfortunate that Toby has suffered this setback but by making this decision now, we don't run the risk of him missing any games," he said.

"No doubt once the surgery has been completed, Toby will vigorously attack his rehab." 

The Giants' younger players begin pre-season training on Monday with the rest of the squad due to hit the track on December 3.