WEST Coast has suffered an early blow ahead of Thursday night's crucial contest against Sydney with marking forward Jack Darling ruled out due to an ankle injury.

Darling had been touch and go all week after tweaking his ankle in the opening minutes of last Saturday's loss to Richmond at the MCG. 

A rare five-day break leading into the Swans clash didn't help Darling's cause and – despite playing out last week's match - the Eagles' medical staff erred on the side of caution with the 24-year-old goalkicker.

"I hate missing games of footy," Darling told the club's website.

"Tonight would have been a great game, but unfortunately the ankle didn't come quite up. The five-day break didn't help. Maybe (with) a couple more days I could have been a chance.

"I'll just get it right and build into training next week and hopefully be right for next week."

Darling, who played every game last season, has been replaced by running defender Will Schofield, indicating All Australian backman Jeremy McGovern could be swung forward.

The winless Swans will go in as selected.

West Coast v Sydney at Domain Stadium, 6.10pm

LATE CHANGES
West Coast: Jack Darling (ankle) replaced in selected side by Will Schofield
Sydney: Nil

FINAL INTERCHANGES
West Coast: Brad Sheppard, Chris Masten, Josh Hill, Jack Redden
Sydney: Harry Cunningham, Oliver Florent, Nic Newman, George Hewett