"We all accept we probably need, in the next month or so, to get about half a dozen players after losing a lot off the wage bill and then selling Glen Johnson and Trevor Sinclair," he says.
"And we have 46 games now instead of 38 so any mathematician would say we need some squad players.
"There are a few things bubbling along so hopefully there will be some activity between now and the start of the season."
On the surprise sale of Glen Johnson to Chelsea for £6m, he says:
"Nobody would have believed, if you had said a month ago, that Glen Johnson would be sold; to a certain extent it was circumstances with Chelsea and the Russian situation.
"Obviously he is going to be an England squad player in the next couple of years so they identified him as somebody they want now.
"The fact of relegation has always been X amount of money would have been needed to make sure we pay all the players' wages and such that we want to next season.
"That was never hidden and with the gap of the £15m, the satellite money, the fact is that was the first significant offer.
"Naturally everyone was loathe to do it, but it meant a significant bit of relief on the financial side for the rest of the season - it was circumstances.
"The fact is you have got to bring X amount in and do you sell six players, four players, who knows?
"You then react to whatever the market is and the fact that it enabled us to get that sort of figure for Glen, after only 14 matches and as a right back with the potential he has got, you look at the other positions.
"As much as anything, with sides trying to frustrate us, you are going to need the ability to score goals and naturally you try and prioritise and think 'can you get away with Glen going as a right back?'
"If you were in the Premiership the answer would be 'no' and for the future the answer is 'no' but in the position we find ourselves it was one of the deals you probably had to do - as loathe as everyone was to do it."
Trevor insists that the transfer was in the best interests of the club and he adds:
"You look at what happened last year; Leicester had financial problems, Derby, Ipswich, Sunderland this year haven't done a deal and are in all sorts of problems - that is the fact of relegation.
"So to have done that deal so early in the summer was a big factor and really enabled us then, with Trevor's figure, to be where we don't have to do deals.
"That really only happened as a result of the first sale and everybody knows we are not over a barrel as such; those two deals have made a massive difference to where our situation was during the close season.
"People were wondering when we were going to do a deal and suddenly, with two quickly like that, the burden is off.
"We are a lot happier now looking forward and are not worried about looking ahead to the whole of the season; but at some stage we have to bring in the loan players and such like to bolster the squad, otherwise we are too thin."
A significant number of incomings are likely to be loan arrangements, and Trevor adds:
"Sometimes you are going to have a better chance getting a quality player out on loan from a Premiership side than you might trying to buy somebody who is being discarded from somewhere else.
"Naturally it is not a long term situation then where you have got a player who will perhaps help you go up and then stay up because you probably wouldn't be able to get them.
"But you have got to face the reality of the situation everyone is in at the moment and probably those sides that did well last year did it trying to get loan deals and whatever."
Trevor is acutely aware that the start of the season is looming and adds:
"If you can do it timing would be ideal for the start of the season but obviously the shop window for Premiership clubs ends at the end of August so at some stage during the next five or six weeks there will be some loan deals done.
"We have got to try and make sure we do some good ones with Premiership clubs because hopefully they will feel West Ham is the type of club that will at least give the opportunity for those players to develop in the right way because of the way we play our football."
Targets have been identified and Trevor adds:
"We have got a good idea who we want; it is a balance of timing and wages and finances but sooner rather than later would be better because we are two and a half weeks from our first game at Preston - there will be incomings."
As for the fallout of relegation from an emotional point of view, Trevor says:
"You are frustrated but when that fixture list comes out it is there so you can't feel sorry for yourself and, like everyone else, we are all hoping to get off to a good start.
"The fact is the side finished very well in the last three months and got a bit of confidence going.
"We have to try and start off in that way and you only have to look at Leicester and Portsmouth last year to see how their good start got them right to the top.
"They never really had a stumble and let others into it, whereas Ipswich finished quite strongly but had a poor start.
"If you do that you are never really allowed a hiccup at any stage of the season; if you start well you get that early momentum going.
"I think it is something like 15 matches up until October 18th which is the first nine weeks of the season - already a third of your fixtures.
"So by then we want to be sitting where we can be fairly encouraged as to the start we have made."
While there are still rumours about other players possibly leaving, Trevor adds:
"It is a fact that there is always speculation; Glen Johnson would have been buckling down and working hard and he probably wasn't anticipating what happened.
"But you are a professional footballer and you have to get on and do it; you are happiest when you are playing football and when we start the season we want to try and make sure we have got the depth and balance in the squad that gives the lads here the confidence that we really can bounce straight back.
"That means we have to get the players in that gives Glenn the options that in the first half of last season we didn't, with the injuries and so forth.
"At the moment it is a transitional period of trying to get ready for the start of the season and a little bit of uncertainty with a few players going who were out of contract and the squad being a bit thin.
"But we have played quite well in the first couple of warm-up games and the last three months and when we get to that opening game, hopefully - with the balance of the squad being a bit stronger - everyone will be very optimistic."
Trevor also anticipates the emergence of one or two of the youngsters and, identifying Anton Ferdinand and Youssef Sofiane as two potential stars of the future, he adds:
"I think we are hoping that one or two will certainly have an involvement and because of the situation we find ourselves in without the loans here they are getting the chance to impress early on.
"Anton did well in his full debut in Sweden and he is the same age as Glen; I am sure he will get his opportunities this season.
"And if Youssef can stay fit he could do well; he can play out wide or in the middle and he is very quick.
"Again, he is the same age as Anton and those two, after the first game in Sweden, are ones to think about if they can stay fit and grasp the opportunity as Glen did.
"Who'd have thought he'd play in 14 matches as he did - he just got better and better and better.
"But I don't think you have got to get carried away; we are realistic enough to know that we are not going to get through on the squad we have got at the moment.
"We have to do some deals and that will be very important over the next month but if we can get somewhere near what we hope to do - and get everyone fit going into the start of the season - we hope we will get the start that we want."
Speaking of the second of the two games in Sweden, which resulted in a 0-0 draw, Trevor adds:
"Djurgardens are top of the league and that was their build-up to playing Partizan Belgrade in the Champions' League.
"They have played 17 matches of their 28 in the league so they were fully match fit and have two or three decent players.
"It was a good test for the lads after Tuesday's game."