Adelaide United have been warned by Football Federation Australia to toe the line in regards to clearly showing their captain's armband.

Following the farce in the dying stages of last week's draw with the Central Coast Mariners when captain Travis Dodd was substituted and oncoming vice-captain Lucas Pantelis did not take the armband, the Reds have been told they will receive sanctions if it was to happen again.

"The Hyundai A-League rules states captain's armband must be worn at all times," A-League chief Archie Fraser said.

"We have written to the club to remind them and further breach could be a fine and sanction."

Adelaide have been sent a reminder that they must oblige with the ruling which was made to help referees easily identify on-field leaders.