The midfielder received his marching orders midway through the second period after a lunge on Wes Hoolahan, and the Canaries quickly made the most of their numerical advantage as Nelson Oliveira added his second and third goals of the day.
"The sending-off was a major decision. I felt it was a poor decision and one that changed the match," McClaren told the club's website.
"Jacob's feet were on the ground, he was going for the ball – he even got a bit of it – but I think the reaction of the player and the reaction of the crowd affected the referee's assistant and the referee.
"We will look at it again and we will look to appeal."
The result meant that McClaren's side missed out on the opportunity to move into the top six.