Buckley and his assistant Brenton Sanderson copped a $50,000 fine - half of which was suspended - for playing a doubles tennis match with Fed Cup captain Alicia Molik in Perth on Friday.

The Collingwood duo had been given permission to play tennis, but the protocol breach was made when they involved someone from outside of Collingwood's coronavirus bubble.

Buckley and Sanderson had to quarantine away from their players for 24 hours while they awaited the results of their coronavirus test.

Two days later, Collingwood suffered a shock 12-point loss to Fremantle in Perth.

Buckley concedes he was in the wrong over the breach, and it was an unwanted distraction heading into Sunday's game.

"I don't have a leg to stand on," Buckley said of the breach.

"It was a lack of due diligence by me and follow-up and I should have known better, really.

"It can't help (our preparation for the match). You don't need the extra attention, especially when it's away from your primary endeavour, which is to be as good a football team as you possibly can be.

"We let the club down in that regard by a miscommunication and not being diligent enough with our understanding of what we could and could not do.

"I just had a really expensive game of tennis during the week."

Buckley says he understands the criticism that has been directed at him - especially by people living in coronavirus-hit Victoria.

"I'd be frustrated if I was locked down and then something like this happened," Buckley said.

Collingwood vice-captain Steele Sidebottom copped a four-match ban last month for a serious COVID-19 breach.

Sidebottom made a strong return on Sunday, tallying 25 disposals and booting two goals in the 10.1 (61) to 7.7 (49) loss.

But Collingwood's inability to match Fremantle's hunger proved costly, with the Magpies losing contested possessions 151-115, and clearances 45-30.

The loss saw them drop to 10th spot ahead of Thursday night's clash with Sydney at the Gabba.

Australian Associated Press