Collingwood have been fined $20,000 - half of which has been suspended - for breaching list lodgement rules.
The AFL said on Monday the Pies had failed to lodge the details of an unlisted player training with the club.
"The AFL's investigations manager Ken Wood found that the club had breached the list lodgement rules by failing to lodge details of an unlisted player training prior to commencement of their training activities, and that player being ineligible to train with the club," the AFL statement said.
Wood said the Magpies had fully cooperated in the investigation "and this and other mitigating factors had been taken into account regarding the penalty".
AFL general counsel Andrew Dillon handed down the fine, with $10,000 suspended until October 31, 2018.