COLLINGWOOD premiership ruckman Darren Jolly will miss Friday night's clash with Richmond at the MCG owing to a sore knee.

Jolly's injury flared up against Carlton last Friday night and he was unable to train on Thursday at Gosch's Paddock.

Collingwood coach Mick Malthouse said developing ruckman Cameron Wood, who recorded 38 hit-outs and 13 touches in the Pies' VFL loss to the Northern Bullants last Saturday, would come in to replace him for his first senior game since round 10 last year.

"[Jolly] has got a sore knee so it's an important time for Cameron to step up and take over that mantle of No.1 ruck. It's a good opportunity," he said after the session.

"His form's been very good. It was good to be able to pick a player who could come into the side and had form.

"Cameron's form through the NAB Cup was very encouraging and his form back with the VFL has been sound, if not better than sound."

The Magpies still have an embarrassment of riches as far as selection is concerned with just Nathan Brown out with a long-term knee injury and second-year midfielder Ben Sinclair sidelined with a leg fracture.

They also have players pushing up from the VFL with Brad Dick, Tyson Goldsack, John McCarthy and Brent Macaffer all training with the senior side on Thursday.

Malthouse didn't rule out further changes to the side poised to take on the Tigers.

"From there, we'll just weigh up and see how another couple of boys are and if they're okay, they'll play, and if they're not, we'll change the side," he said.

Malthouse named Alex Fasolo, Kirk Ugle and Paul Seedsman as first-year players who could challenge for senior selection this year if they found - and held - form.

He highlighted the big turnaround the Pies' list underwent last year and the "10 or so" youngsters who wouldn't be considered for games this season, but emphasised the importance of rotating those in the frame.  

"It would be very foolish for us to say that our list is right through to 40-odd. It's not," he said.

"That's the list. The VFL will not win every game and they've proven that; they got beaten last week handsomely.

"But, on the same token, three or four blokes put their hand up to play and that's encouraging.

"It puts massive pressure on players to perform at a higher level because we must turn our players over.

"We don't want to go right through the year and find we're not playing these players and when the time comes and they get a game, they're not up to it. We've got to find out early."