With Fredi Kanoute injured in the medium turn, Glenn rues the fact that he was unable to bring in cover by way of a big, physical striker before the end of August as he tried to do.
To add to his woes, Trevor Sinclair and Don Hutchison are on the injured list while Paolo Di Canio, who missed the trip to Liverpool, is also a doubt for Wednesday's game with Oldham Athletic.
All of which adds up to a weakened forward line which Glenn is unable to strengthen by way of permanent or loan transfers until January - when all of those players will hopefully be fit.
"Once we have got through the first dozen games, at this time of the year clubs are more likely to pick up injuries," he says.
"I don't see that there is any need to change things. It is certainly not to our advantage anyway, and it isn't for most clubs of our size.
"There are quite a few clubs operating with a small first team squad, and if they pick up three or four injuries they are going to have the same sort of problem.
"At a time when things are very tight in football, transfer windows have made clubs try to increase their squads - when they can ill afford to do it.
"The transfer system worked very, very well for many years and I have always advocated that if it is working well why tinker around with it?"
The reasoning behind the imposition of a transfer window in this country is considered by most to be, at best, spurious, and Glenn adds: "There are reasons which I don't want to go to in length, and there are arguments put up by the people concerned that impose transfer windows but they don't wash with me."
Nonetheless, Glenn has to get on with what he has got, and he adds: "If someone gets injured it gives someone else gets the opportunity - and he has to take it.
"They have to prove they are good enough and you would certainly think the ones that come in would be highly motivated to show they are capable of playing at the standard we require."