UEFA defines 'transfer balance' as the difference between cost savings from outgoing players and the new costs from incoming players at the time of the club’s List A submission. In simple terms, any spending to add players to Villa's UEFA List A squad must be offset by the income generated from player departures.

Chelsea and Aston Villa have been fined by Uefa for breaching the European governing body's financial rules.The two clubs could be prevented from registering new players for Uefa competitions for the forthcoming season unless they have a positive transfer balance by the end of the summer transfer window.

Chelsea have been fined €31m and could be fined a further €60m if they do not comply with the rules in the next four years. Villa have been fined €11m, with a further €15m conditional on compliance in a three-year period.