"As everyone could see he tried to carry on for as long as he could which is all credit to him," says Glenn.
"He could quite easily have come off at half time, he carried on for as long as he could, but in the end it was impossible for him.
"He has that tear in his cartilage that has been operated on and it is a massive blow to us that we will be without our leading goalscorer, who has been a massive influence, for eight weeks."
It confirms that Glenn now needs to bring in two strikers and he adds:
"We must have the opportunity to bring in the sort of cover that we need."
It is not the end of Glenn's injury problems.
"Richard Garcia is out for six weeks with a fractured shin, Steve Lomas will playing in the reserves on Tuesday and then he is definitely in contention for Old Trafford, and we hope Don can play in that game, but he needs more sharpness - but he has done well to get through two 90 minute reserve games.
"We need Fredi fit as soon as possible, but it seems we have been saying that for about a month, so I won't say too much until we see him in a first team shirt."
Meanwhile, Glenn says he has no idea where the story came from linking Gillingham with a loan bid for John Moncur.
"That was news to me; I haven't spoken to Andy Hessenthaler about him and and far as I know no one at Gillingham has spoken to us about him.
"We need all the bodies we have and I took a liberty with John asking him to be on the bench on Monday after literally one training session in seven weeks."
As for comments by Harry Redknapp this week, he says simply:
"All I can say is that I don't think about Harry, I certainly don't talk about him, and that is the end of it."
And, commenting on speculation that he has been looking at a player each from Auxerre and Monaco, he says:
"They even got a name wrong; it is speculation and I don't know where it has come from."