The prominent barrister who helped Cardinal George Pell win his appeal at the High Court is advising Football Federation Australia of its contractual rights in the game's standoff with Fox Sports, who could terminate the broadcast deal if the A-League does not resume by June 30.

Sources with knowledge of the deal suggest Fox Sports will have to pay the final quarterly sum for this season, due on April 15, but could issue FFA with a breach notice if the A-League remains postponed by the end of this financial year.

Barrister Bret Walker, SC (left) is advising FFA through its looming broadcast clash with Fox Sports. Credit:AAP

Under the terms of the contract, the FFA is free to postpone the A-League season without punishment so long as they complete the entire season within a contract year, which runs from July 1 until June 30.

FFA is due to decide on April 22 as to whether the season can resume but there appears to be very little prospect of play being resumed in the short term. Senior A-League sources are touting a possible return date in July, but even that isn't certain.