|
A tribunal will decide the transfer fee as the two clubs could not come to an agreement.
When polled last month, more than two-thirds of Iron-Bru.net users backed his return to the club.
Hayes moved to Barnsley two years ago after rejecting the offer of a contract to stay at Scunthorpe following promotion to League One.
He helped them seal promotion to the Championship in his first season, scoring in the League One play-off final.
But he fell out of favour last season, and moved on after a disagreement with Tykes boss Simon Davey.