Giants star Lachie Whitfield has been officially ruled out of Saturday's preliminary final clash against Collingwood.

Whitfield was taken to hospital on Tuesday night and diagnosed with appendicitis.

He underwent surgery on Wednesday morning to have his appendix removed, with the possibility of a grand final return if GWS qualify.

Giants coach Leon Cameron confirmed his side will be without the star utility when they take on the Pies.

"We’re confident it will just be one week," Cameron told reporters on Wednesday morning.

"He obviously can’t play this weekend but we’ll be doing everything in our power to win this weekend and give him the opportunity to return if we progress.

"It is what it is, these things happen. His health is more important than any game of footy."

The Giants will also likely be without suspended star Toby Greene for Saturday's clash, unless his ban is overturned by the AFL Appeals Board on Thursday night.

"We’ll appeal Toby’s suspension because we believe we have a really strong case. We’ll plan for Toby in and we’ll also plan for Toby out, Cameron added.

"You can’t replace Lachie Whitfield and Toby Greene (if needed) but it does provide opportunities to guys who are itching to get out there and play their role. This group is very adaptable and we’ve learned to deal with lots of setbacks over the years."

Collingwood and GWS will meet at the MCG on Saturday at 4:35pm, with the winner advancing to the grand final.