Collingwood forward Mason Cox has been ruled out of the Magpies' clash with Port Adelaide on Friday night.

The 211cm giant suffered an ankle injury after being accidentally trod on by Essendon's Michael Hurley on Anzac Day, but could be fit in time for the Magpies clash against Carlton the following week.

Cox's injury paves the way for Ben Reid to play his first senior game in 11 months after impressing in the VFL. The 30-year-old has kicked eight goals in four games and has been named in the Magpies best on four occasions in the VFL this season.

Small forward Jamie Elliot is also likely to return, after recovering from a corked buttock that sidelined him against Essendon.