The stylish Yugoslav defender suffered a muscle strain practicing set pieces at lunchtime on Wednesday, giving Anthony Gardner the chance to make his first start of the season.
"Goran would have played," said Glenn. "He got a slight muscle strain, otherwise he would have played. Anthony Gardner did ever so well, he didn't know he was playing until lunchtime. He came in and was magnificent and proves there is competition for places.
"He is another player who can only get better and better."
Glenn added that Les Ferdinand was withdrawn at half-time after notching a hat-trick as a precaution after taking a blow to his previously injured ankle.
"Les got a knock on the far side right on the same spot as before half way through the first half so we decided to take him off.
"It was not a bad time to take him off - he already had the ball under his arm!"
Good news on the injury front is that long-termers Gary Doherty and Stephen Carr could possibly be available for selection towards the end of January.
"Gary Doc is on his way back, him and Stephen Carr are running mates at the moment - round the training ground and on the treadmills.
"We would hope to get them back probably at the end of January."
Glenn revealed that Goran Bunjevcevic would have featured against Bolton had he not suffered a slight strain in training ahead of the match.