"Trevor Sinclair has withdrawn from the squad simply because he is just still too unwell," says the Hammers boss. "What we thought was a heavy cold has developed into a quite severe case of flu.
"It is a great disappointment for him because he has been doing so well lately, but I am sure in the big picture it won't damage his chances of getting into the England World Cup squad, because there are more friendlies to come.
"I am sure he will carry on playing the way he has done for us this year and Sven-Goran Eriksson will pick him again to give him another opportunity in an England shirt.
"I don't see any reason why not; there is still enough time and games for Trevor to impress."
The Hammers should still have England representation in the form of David James and Joe Cole, however, and Glenn adds: "I am obviously pleased for David, and I am keeping my fingers crossed that he plays again against Holland. I am hoping he is selected to start the game.
"I am sure that at least two of the goalkeepers will play on the night and of course Joe is also back in the full England squad.
"Joe takes defeats probably worse than anybody. We were all really disappointed at Bolton and Joe was quite devastated, especially as he is trying so hard at the moment to make a goal or score a goal.
"He was pretty fed up after the game but when I told Joe afterwards he was in he was delighted - and it put a smile back on his face.
"When Mr Eriksson phoned to tell me we had three players in the squad he also asked about Michael Carrick.
"I can vouch for the fact that our dressing room wasn't a pleasant place after the game, though - everyone took it badly, which is the right thing to do because it shows they care."
England's next friendly after the Holland game is on March 27th against Italy at Elland Road.
The illness means that Trevor will not play for the rest of the month as he is suspended for the home game with Middlesbrough.
*West Ham fans can see what goalkeeper David James has to say about his call-up to the England squad for Wednesday's friendly against Holland in Amsterdam by visiting our fantastic Hammers VideoLounge.
David took part in a press conference on Monday at the England training headquarters and Hammers fans can view his video interview by clicking here.