Hull manager Phil Brown hopes referee Lee Probert admits he was wrong to send off George Boateng.
The former Middlesbrough midfielder was dismissed for a challenge on Morten Gamst Pedersen as Hull lost 1-0 on Wednesday night.
Brown said: "George can't believe it, I can't believe it, and hopefully Lee Probert will look at it and he won't be able to believe it either.
"For me, it was a poor decision. I'm not saying the game hinged on it, but the referee reacted too quickly.
"It was a clash of heads with two players going for the ball. George was unconscious with a head injury and you can tell by the reaction of the players that it was impulsive.
"The word 'frivolous' has been attached to the appeals procedure, but the decision could have an effect two or three games down the line if George gets a suspension."