Former Port Adelaide star Kane Cornes has outlined five reasons why he believes 2020 could be Nathan Buckley's last chance to win a premiership at Collingwood.

The Magpies legend's resume over a 23-year career as player and coach is as decorated as they come - seven All Australians, six best and fairests, a Brownlow Medal, Norm Smith Medal and three grand final appearances. The one thing missing? A flag.

Collingwood fell agonisingly short of rounding out Buckley's trophy cabinet in 2018, losing to West Coast in the grand final by under a kick. Last year, the Pies went down to the Giants in the preliminary final by five points.

And Cornes believes it could be now or never for Buckley's men.

“(He has had) 14 years as a player, nine as a coach, that’s 23 years (for) the illusive flag. I think this could be the last roll of the dice,” he said on Channel 9’s Footy Classified.

“There’s five reasons why I think this could be Nathan Buckley’s last shot at a flag at Collingwood.

CONTRACT CONUNDRUM

“Reason number one is the contract conundrum situation with a number of their players. In particular, Darcy Moore and also Jordan De Goey,” he said.

“With the salary cap squeeze and also a reduction in that, I think it is very difficult and very unlikely that both of those stay. I think it is more realistic that one of them go.

VETERANS’ DAYS NUMBERED

“They aren’t getting any younger. Pendlebury will be 33 years of age by Round 1 next year, Steele Sidebottom has played a lot of footy, he’ll be 30 this time next year,” Cornes said.

“And those two, perhaps their best footy is now and we won’t see the best of those two moving forward.

FAILING THE FITNESS TEST

“Their injury history has been devastating for the club,” Cornes added.

“They’ve had a number of key players suffer chronic injuries, from Elliott to Darcy Moore himself. There’s been Taylor Adams, (Matt) Scharenberg, (Tom) Langdon is another one.

“With list reductions coming, if they are to have similar setbacks to what they had in the last five to 10 years, that could be devastating for the club.

BEAMS BLUNDER BITES

“The Beams blunder. Not only is the financial situation with the contract with Dayne Beams, it is two first round draft picks to get him,” he said.

“Two young players that have had a year under their belt in the system, they’ve got nothing to show for Dayne Beams which will definitely cost them in the future.

CAP BRINGS THEM BACK TO THE PACK

“If there is a hard cap on spending, Collingwood has always used the extra resources, best medical, best fitness staff, best coaching staff, best facilities. Well they are going to come back to the pack,” Cornes explained.

“I think there is going to be a hard cap on spending if it’s five million and Collingwood can’t go over that.

“It has been 23 years, I think this is could be his last roll of the dice and last throw at the stumps.”