McPharlin had originally been named in the extended squad after passing a fitness test on Thursday afternoon.
However, the key defender was withdrawn from the squad with calf soreness.
He has been replaced in the side by ruckman Jack Hannath.
Defender Zac Dawson has also suffered a setback in his recovery from injury.
The former St. Kilda defender has been battling a groin issue and was set to return this weekend through the WAFL. But coach Ross Lyon said that he will sit out at least one more week.
“No he won’t play this week but he’s out there training,” Lyon said.
“He’s feeling really good, we just thought we’d give him some more build-up. He just pulled up a little bit sore in an unrelated spot, so it just put him back a day.”
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