AFL legend Gerard Healy has declared that Toby Nankervis' move to Richmond at the end of 2016 was Sydney's worst list management error in 20 years.

The big man has established himself as one of the most competitive ruckmen in the competition since joining the Tigers ahead of the 2017 season - helping the club win three premierships with his tough grunt work at stoppages.

But before he donned the yellow and black jumper, Nankervis struggled for senior opportunities at the Swans.

He managed just seven games over three seasons at Sydney, having been stuck behind Kurt Tippett and Sam Naismith in the pecking order.

Fast forward four years and he is one of the strongest assets to the league's biggest powerhouse, while the Swans have struggled to establish a reliable No. 1 ruckman.

Callum Sinclair of the Swans (L) competes against Toby Nankervis of the Swans (R) during a Sydney Swans AFL training session at Sydney Cricket Ground on September 13, 2016 in Sydney, Australia. (Photo by Matt King/Getty Images)

Speaking on 3AW’s Sportsday, Healey believes Sydney's Nankervis trade blunder is comparable to the Tom Mitchell deal, stressing how John Longmire's ruck debacle has since haunted them.
“Now, the Swans have picked up a lot of good players over the years, value players. (But) probably the biggest mistake they’ve made as a recruiting group in the last 20 years was letting Toby Nankervis out of that place,” Healy told Sportsday.

“Mitchell was nearly their best player in a Grand Final the year that they decided to trade him. Mitchell was a shocker, but Toby Nankervis has also been bad because the Swans have been desperately looking for a ruckman ever since.

“They’ve gone to the west and picked up two (Callum Sinclair and Tom Hickey), they’ve had kids coming out of rugby union clubs trying to get them to become a ruckman – Toby Nankervis was there waiting for you, fellas. And he’s gone on to become a multiple premiership player and a star.

“You don’t have to be a genius at the ruck craft to be a genius as a ruckman.”

Nankervis has played 82 AFL games since being drafted by the Swans with Pick 35 in the 2013 draft.

He turns 27 later this year.