The club were unwilling to pay £750 to fund a challenge without a solid case, and Horsfield would have risked an increased suspension – potentially doubled – had the Football Association considered his appeal to have been frivolous.
His three-match suspension could yet be stretched if the FA decides to investigate his subsequent exchange with linesman Phil Sharp, who recommended the dismissal to Styles, but Blackwell has already resigned himself to losing Horsfield until the visit of Wolves to Elland Road on September 10.