Shaka Hislop, Craig Forrest, Paul Kitson, Steve Potts, Omer Riza, and Michael Ferrante will not be receiving renewed contracts this close season, but Izzie Iriekpen, Nigel Winterburn, and John Moncur - whose contracts were also up - will all be staying.
Sven Andersson has completed his short term contract at Upton Park, and is also going.
The exodus means that the goalkeeping and striking positions are under particular scrutiny, but Glenn insists he will not be rushing into signing replacements just yet.
Explaining the thinking behind some very tough choices, Glenn says:
"We are probably one of the last clubs this year to let it be known who is being retained and who isn't.
"There have been some difficult decisions to be made but every single player that is leaving goes with my good wishes and thanks for the service they have given to the club.
"Hopefully they will get fixed up, as in the case of Adam Newton, who has already got sorted out at Peterborough.
"That is terrific, and he is on a similar sort of deal that Tommy Williams and Jimmy Bullard went on, with a sell-on clause.
"I am sure that all the other players will find clubs and continue elsewhere, except Sven Andersson, who is going to retire, as he had done just before he came to us from Helsingborgs.
"Although our supporters never saw him play, he helped us out greatly."
Glenn says bringing in another keeper is one of his priorities, and reveals:
"We are on the lookout for an understudy to David James, and obviously young Steven Bywater and David Forde will be fighting hard next year.
"But I still feel we need another goalkeeper; I am interested in a couple at the moment, which will obviously remain private, but hopefully we will find one of sufficient quality to be up to the job if he has to play."
Of Shaka's departure, he says:
"It is always difficult when you have been a number one goalkeeper, and he has been one for a number of years, wherever he has been.
"It was obviously hard for him being a number two, and he said so - which was no problem to me - but he never complained, never came in and caused me any problems, and I am very grateful for that."
Shaka played the first 13 games of the season, and Glenn says:
"I always knew that if I had to call on him he would come in and do a good job; he has been a terrific servant for the club and I am sure he will have no problem finding a new one."
It was a surprise to some that no one looked to buy him last season when David James returned to fitness, but Glenn says:
"There weren't too many clubs last year that were one, in a position to buy, and two, needed a goalkeeper last season.
"But with everyone moving their squads around things will change, and I am confident Shaka will get fixed up at a decent club and will carry on being a number one again."
The third keeper to depart this summer is Craig Forrest, well on the road to recovery following an operation for testicular cancer earlier in the season, and Glenn says:
"Craig has got to decide what his future has got to be, and the only thing that concerns us now is that he has got over his illness and has a full and healthy life - which I am sure he will continue to do.
"We are waiting to hear from the specialists, but Craig has got to make the decision whether to carry on or not to - and only he can make that decision."
The longest server to go is, of course Steve Potts, and with his release the last playing link to the John Lyall era.
"Steve Potts has been a fantastic servant to the club; him and West Ham go together hand in hand," says Glenn.
"He has been here since he left school; it is so rare now that you get a one club man, but we felt at 35 it was time for him to decide where he is going to play.
"I have spoken to Steve, he is going to continue, which I am pleased about, and I think the time for him to get involved in first team football again has now come.
"Hopefully he can find a club not too far away as he won't want to move his family; his young son Daniel is in the academy and doing really well, so hopefully Steve will get fixed up with a local team and get a contract for at least a couple more years.
"I would like to thank him for all the hard work he has put in and the attitude he has shown; when I was working with the reserves before I became manager I often has Steve in my group, and he always showed a fantastic temperament.
"If any potential new club comes on to me I will be giving him the five star treatment, because he deserves it - he is a coach's dream.
"Of course, he has to look at his own long term future and see whether he goes into coaching players himself; I know he is working hard on his coaching badges now."
Supporters were hoping that he would get a run on the last day of the season, thus completing 400 league games and 500 overall for the club, but Glenn says:
"He understands, and I don't even think that is a point of discussion; he is a terrific professional who has been brought up in the right manner, under the influence of John Lyall.
"He wouldn't want to be put on just for the sake of it, he'd want to be put on to go and do a job, so there are no problems there whatsoever; we needed to win the game, which fortunately we did in the last minute."
Another player to go is Paul Kitson, whose opportunities have been limited in the last two campaigns but whose partnership with John Hartson after he initially signed from Newcastle proved invaluable.
"Paul has been very good this year; again, a senior player used to playing first team football for whom it is difficult only being on the bench," says Glenn.
"But his attitude has been very good for me and when I have asked him to play he has gone and done a job, none more so than at Charlton when he stuck in a hat trick with three terrific strikes.
"I also remember the game at Chelsea when him and Defoe did particularly well up front.
"I am sure he still has a lot to offer football, and he needs to play week in week out again at the age of about 30.
"What he did for us this year, albeit with limited opportunities, proves he can still do it at the highest level, so I am hopeful he will get fixed up at a decent club."
His absence next year will leave the club shorter on striking options if he is not replaced, and Glenn adds: "We are always on the look out for strikers; it is a difficult position to fill, I am viewing one or two options but again, it is whether I can get them into the club."
Another striker, Omer Riza, never made the breakthrough since signing from Arsenal for £25,000, but Glenn says:
"I think Omer Riza won't have any trouble; he is a young player that needs to get first team football now just as Adam does.
"He has already proved that he can handle the second division when he has gone on loan; I saw him play for Cambridge a few times and he did really well, so I'd be surprised if he doesn't get fixed up at a decent club and gets his career going, playing with the men in first team football.
"I worked with him and coached him for quite a long period and he was a pleasure to deal with."
As for the three players who were offered new deals, Glenn says:
"I am very pleased that Nigel has signed and he has earnt it purely on merit; there is very little room for sentiment in football and he deserves his year's contract.
"John Moncur is the same; he is going to take another year, and I think, as with Nigel, maybe look to call it a day at the end of next year.
"It is very possible that John could have a career in coaching; he has certainly got the knowledge and he tells me has already qualified with his coaching badges.
"I know he is delighted to be staying at West Ham; he has a terrific rapport with the supporters and I am happy to have John and Nigel's experience around the place next year."
Both players were desperate to stay at Upton Park, and Glenn had actually told Nigel he would be released until he agreed to a pay cut, and Glenn adds:
"I am very pleased that both lads took the sensible view; football is going through difficult times at the moment, both boys really wanted to stay at West Ham, and we have been able to give them that opportunity which they have taken up.
"Those two boys are off on their holidays now looking forward to the 4th of July and coming back to West Ham."
As for the third of the players offered a new deal, Izzie Iriekpen, Glenn says:
"We are in talks with Izzie; it is only the middle of last year we thought his career was over, but he has made a miraculous recovery on his knee and I have been pleased with what he has done.
"He has lost two years of his playing career, which is a dreadful shame, because it is very possible that he could have come up to the sort of level that we would have wanted him to.
"But we want to give him that opportunity next year, and hopefully we can get an agreement in the next week or so."
Players out of contract will not necessarily be the only players leaving, and two centre halves, Hayden Foxe and Raggy Soma, have been in talks with Portsmouth and Austria Vienna respectively.
On that, Glenn says simply:
"There is nothing to report at the moment."
So what of the incomings?
"It about weighing up all the options and not making any mistakes," says Glenn.
"I don't want to be taking someone in today and then in two or three weeks' time I wish I had waited because something else appeared that was better."
Glenn says patience is the key tactic as he looks to strengthen and adds:
"I am trying to keep as many irons in the fire as possible and then decide which way to play those options, probably in the middle to the end of June.
"We will hopefully make at least three or four signings."