Williams has been a standout on the training track for the Magpies for the past two months after declaring himself ineligible to play at AFL or VFL level in February.
He has now made himself available for selection.
Magpies coach Nathan Buckley warned Williams' emotional state might override his desire to play this week, while captain Scott Pendlebury confirmed on Thursday the club was still wading through the issues surrounding Williams' return.
The Magpies' VFL team will welcome back defender Paul Seedsman, who has overcome a hip complaint, while highly rated youngster Tim Broomhead will also make his return.
Broomhead broke a bone in his hand in the club's first NAB Challenge game against Geelong, while shin splints have slowed his recovery since. That follows a bout of glandular fever that hampered his debut season in 2013.
Collingwood will make a call on Williams' availability in the next 24 hours.
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