COLLINGWOOD talls Jesse White and Ben Reid must prove their fitness at Wednesday's training session to win selection for Friday's season-opener against Fremantle.

Coach Nathan Buckley says Reid and former Swans forward White, who are battling calf muscle complaints, will be under pressure to train strongly.

The injury doubt over White leaves 35-year-old back-up ruckman Ben Hudson in the frame for selection as the Magpies seek to counter Fremantle's triple All Australian Aaron Sandilands.

Hudson, a mature-age rookie, was upgraded to Collingwood's senior list on Tuesday afternoon as the PIes sought to keep their options open at the selection table. 

"We definitely need tomorrow's training session to be positive about the make-up of our final 22," Buckley told reporters on Tuesday.

"We won't be taking any risks with any of our players."

Buckley said the 211cm Sandilands was clearly a challenge to Collingwood's hopes of winning Friday's game at Etihad Stadium.

"We've got a couple of young ruckmen we can put in against him, some really good options," Buckley said.

"Jesse White if he gets up, Quinten Lynch, Ben Hudson for that experience."

Lynch, who played 18 games last year at Collingwood after crossing from West Coast, is another player who could benefit from the injury doubts over Reid and White.

Collingwood's No.1 ruckman Brodie Grundy is coming off a promising seven-game debut season in 2013, but the 19-year-old will need back-up against the imposing Sandilands.

"Jesse White will train tomorrow to stake his claim," Buckley said.

"Ben Reid will have to train strongly tomorrow."

Buckley noted most judges were tipping runners-up Fremantle to go one better in 2014.

"(Coach) Ross Lyon has said himself they're probably three weeks shy in their pre-season so it's not a bad time to have a real crack at them," Buckley added.

Defender Alan Toovey will play on Friday in his comeback from a season-ending knee injury which the 114-game veteran suffered in round five of 2013.

"He has three pre-season matches under his belt now. We expect him to be right," Buckley said.

"His teammates will walk taller around him."

Sam Dwyer, Josh Thomas and Alex Fasolo have been ruled out for Friday's clash because of a lack of game-time during pre-season.