Hearts have admitted to "inadvertently" fielding an ineligible player in their Scottish League Cup group-stage victory over Cove Rangers.
The club will face a hearing on Monday after Andrew Irving, 18, came on in the 65th-minute of Wednesday's 2-1 win.
Chief executive Anne Budge spoke of Hearts' "embarrassment" after admitting they failed to register the player's new deal, which he signed in January.
"While stringent processes are in place, mistakes can happen," she said.
Budge, who apologised to the fans, Cove, and the football authorities, added that the club would add an "additional step in our internal procedures" to ensure there is no repeat,
Hearts representative will attending Monday's Scottish Professional Football League hearing, where sanctions will be determined.
In 2016, Cove were themselves fined £2000 for naming an ineligible player as an unused substitute in a 4-0 defeat by Alloa Athletic in the same competition.
However, Albion Rovers were thrown out of the Challenge Cup - also an SPFL competition - in addition to their £2000 fine for fielding Liam McGuigan in a 3-0 win over Spartans last season.
Hearts' win in the first competitive game at the Highland League champions' new Balmoral Stadium put them three points behind Inverness Caledonian Thistle in their group with a game in hand.
The Edinburgh side missed out on qualifying from their League Cup section last season after they finished behind Championship side Dunfermline Athletic and Peterhead of League Two.