Watford have confirmed they will challenge an FA independent panel decision to dismiss the club's appeal against Etienne Capoue's red card at Leicester last Saturday.
Capoue was sent off in the dying seconds of the match following a challenge on Leicester's Kelechi Iheanacho.
"We are very disappointed that a majority of the Regulatory Commission has upheld a decision which nearly everyone considered to be an error," Hornets chairman Scott Duxbury said in a club statement.
"The only process by which we can challenge the decision is via arbitration under rule K of the rules of the Football Association.
"That is something which cannot be achieved before our next game this evening, but we will be striving to ensure a hearing is held before the end of this week."
Capoue misses Tuesday's game against Manchester City, and he will also sit out appointments with Everton and Cardiff if the ban is not overturned.