The People says Hearts are asking FIFA to sanction a £4.6m 'fee' for Webster in a test case.
But FIFA fined him £625,000 for making the move. However, Hearts are not satisfied and a final FIFA decision will be made next month in the biggest case since the Bosman ruling changed football.
If Wigan have to cough up it will be a sensational twist, especially as the player has since moved on to Rangers. Webster - currently on loan at Ibrox - is still registered with Hearts until the dispute is settled.
Some of the biggest stars around are waiting for FIFA's ruling as it will affect every player who has a year left on their contract.