Following on from the sale of fellow defender Rigobert Song for less than the fee paid to acquire him, Glenn has been forced to take a financial 'hit' on behalf of the club to move players on who are not in his first team plans.
He explains:
"It is very difficult and the market is as flat as it has been probably in the history of the game.
"There are one or two exceptions, such as the obvious one of Manchester United spending £30m on one player, but there is so little activity at the moment.
"The easiest thing to say would be that it is unbelievable but it is not: we knew that the amount of spending that has gone on in previous seasons and the increase in salaries that had gone through the roof was going to take its toll.
"Now it is starting to bite, and bite really hard - Europe is in a mess at the moment."
The situation is not just hitting players in the pocket, but their representatives as well.
"I have to deal with agents every week and they are finding it difficult to put deals together to earn any money," says Glenn.
"They have obviously made plenty of money in past seasons but the agents will tell you they are not doing any business at the moment.
"The majority of clubs in Germany, Italy, Spain, everywhere - even France - have no transfer funds, and everyone is trying to take players without paying a fee for them.
"I think this is only the beginning, I don't see it as being just a blip for a year or so; I think it is the start of the transfer market changing to something completely different to what we have known for years and years."