Hull City interim manager Mike Phelan questioned the decision to send off Jake Livermore as the Tigers fell to Arsenal 4-1 on Saturday.
Fans at the KCOM Stadium were audibly upset with some of decisions of referee Roger East, particularly when he adjudged Livermore deliberately handled the ball in the 40th minute.
"My only question is was it a deliberate handball, which made it a sending-off," Phelan said after the game.
"We all have hindsight afterwards when we see everything replayed and what have you, but I don't think it was hand to ball, I thought it was more ball to the arm.