Christian saw red right at the end of normal time for a challenge on Charlton's Scott Parker, where contact did not appear to be made. He was first booked for a trip on Kevin Lisbie after 55 minutes.
"Very harsh," said Glenn afterwards. "Scott Parker has said he didn't touch him and, in my opinion, I didn't think there was contact made.
"It is the referee's decision, whether he can have a look at it and change it, we'll wait and see. It was very harsh for him.
"He is distraught, with it happening twice in a week. What we have got to say is, Christian is not somebody who elbows people or does over the top tackles.
"But he has been sent off and it is disappointing for him and for us."
Glenn feels that Christian Ziege was hard done by in receiving a second dismissal in four days against Charlton.