AN ANKLE injury has ruled Collingwood giant Mason Cox out of the big clash with Port Adelaide at Marvel Stadium on Friday night, with forgotten veteran Ben Reid to receive a welcome 30th birthday gift by being promoted for his first AFL game in 11 months.

Reid's task as a key forward will be assisted by the return of the dynamic Jamie Elliott, who has been passed fit after missing the Anzac Day blockbuster against Essendon with a corked buttock.

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Cox, who notched his 50th game on Anzac Day and has played 29 of the past 30 games, including the past 16 in a row, suffered the ankle injury after being accidentally trod on by Essendon defender Michael Hurley, but could return the following round against Carlton. 

The 'American Pie' wasn't the only prominent Magpie not to be sighted at training on Wednesday, with star midfielder Adam Treloar also a no-show. However, Collingwood coach Nathan Buckley revealed Treloar's workload was simply being managed after completing a power of work so far this season.

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Defender James Aish will be sidelined for at least another game after failing to overcome the bout of concussion he sustained after copping a knock to the back of the head against his former club Brisbane in round five. 

Meanwhile, Buckley said veteran runner Daniel Wells still had "work to do" to before being considered for a return at AFL level, despite performing well in three successive VFL games since recovering from the foot injury that sidelined him for the bulk of last season.

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Reid, the Pies' 2010 premiership centre half-back, hasn't played at AFL level since round 10 last year when he suffered yet another soft-tissue injury, which led to him missing out on the Pies' charge to the Grand Final.

Reid, who turned 30 on Monday, has been a shining light in the Pies' VFL side, taking swags of marks and kicking multiple goals.

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Entering his 143rd AFL game, he will be expected to play Cox's dual forward/ruck role, providing support for Brodie Grundy against Power duo Scott Lycett and Paddy Ryder in what is likely to prove a critical battle for ascendancy at stoppages.

Buckley paid tribute to the injury-plagued swingman for his persistence to overcome a series of injuries in recent seasons.

Ben Reid is finally back. Picture: AFL Photos

"Our best-performed VFL player over the last month has been Ben Reid and he's been in great form, and he has been doing a bit of ruckwork as well so it's a bit of a like-for-like replacement and reward for a really good block of form," Buckley said after training on Wednesday.

"When you've been part of the furniture at AFL level, premiership player, the game has changed, (his) role's changed and you've had the injury concerns that he's had, they're all obstacles that you have to jump over at some stage and over the last three or four years Reidy's really been tested. 

"But his preparation through pre-season was as strong as ever and his body's in as good a shape as it's been for a long time.

"I'm sure that when he first had his injury concerns he would’ve thought, 'If I can just get my body right, I'll be right.' A lot changes pretty quickly and Mason's jumped up in front of him and Brody Mihocek's jumped up in front of him, but this is a chance for 'Reidy' to come in and contribute and stake his claim.

"His teammates are rapt for him. He doesn't need to be a world-beater but he comes in and assumes the role." 

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The Pies are wary of the challenge posed by Port Adelaide, which has also started the season strongly with a 4-2 record. 

"They're taking the game on flat out, they've got young blokes buzzing around and putting a lot of pressure on, hunting ground ball, hunting contested ball … and winning a lot of those contests and running out of (them) in waves, so they ask a real question in that regard," Buckley said.

"They're defending as aggressively as anyone in the competition from behind the ball … and they've played as consistently as anyone. They're going to be a real handful."