"It is an ongoing one at the moment and a case of being aware of who is up for grabs. We will need to get some players in with the 10 players having dropped off the wage bill," he says.
"Five or six of those would probably have been regulars in the first 16 so we do need to have people come in, but there will still be a situation probably where one or two have to move on as well.
"Until we know who is going, who is staying, and in which positions, it is a case of keeping an eye on the comings and goings and making people aware that we might be interested.
"But, as usual, June is a time when everyone goes away, and if you are interested in somebody they might wait until that is out the way - and then deals are done once everyone is starting to come back.
"July is the busiest of months and there will be a lot of behind the scenes activity then.
"Lists have been gone through with the likes of Paul Goddard, Roger Cross, Paul Aldridge, and one or two of the scouts, about the likely positions in all parts of the squad that we would be interested in adding to.
"It is a balance, really. You get the older players coming to the end of their term probably looking for a couple of years, whereas most clubs will probably be only willing to offer a year at the moment.
"Then there are players that might be good to do a job in the first division but might not perhaps be ideal to take back into the Premiership if we do well.
"So the area we have got to be looking at is to try and find somebody who can be a good squad man or in the team but also are they a first division player who can help you get up with the nucleus we are trying to keep or are they somebody you can also take back into the Premiership?
"What you don't want to do is lock yourself into players who might be good for the first division but not good enough for the Premiership.
"What we have to be looking at is getting a good start and also being able to bounce back, and the requirements for getting back in 12 months are different to taking two or three years to get back.
"I think the club have got to look on the positive aspect of trying to make sure we devise a strategy that gives us a good start and enables us to not tie ourselves up into too much long term."
Is there a fixed number of players the club is looking to bring in?
"I don't think so, because the other key area is the loan deal situation," he says, "and we can do loan deals now from the Premiership - up to five, I think, during the season - which is something else the club need to be looking at.
"At the start of July we might not have a squad that has sufficient depth and we might have to build it over the pre-season - I think that could be the case at a lot of clubs.
"What we start with in July might not be what we have on the 9th of August for the opening game."
As well as acquisitions, Trevor is also looking at some of the young players breaking through, and he adds: "At the back, Anton Ferdinand and Elliott Ward are defenders who have done well for the under-19s and you would like to feel come into the equation next year.
"Richard Garcia is on the fringe of it and you would certainly think he would be an option in midfield or up front in Division One.
"There are one or two others who have had to be patient - Shaun Byrne is another one who could be used in midfield if he can stay fit, so it is a case of looking at those.
"But we are conscious that we need experience and quality that is used to playing in that division, and can go to some of the away grounds and can really graft and knuckle down to battle out results where you can't play the football you would like to play.
"So it is a whole mixture and blend that you would like to get right over the increased number of 46 games - and that will require players to come in and do the job."
Up front is a particular concern and Trevor adds: "We found out last year that starting with three strikers wasn't enough really - and here we are going from 38 games to 46.
"So we are going to need four good strikers supplemented by one or two people that can certainly do a job elsewhere like Don Hutchison and Trevor Sinclair.
"That is an area we are focusing on but it is the most costly area. We have to argue the case and some players will be tempted to go to the Premiership.
"But we would like to feel that people will like the way we try and play football and think we have a good chance of bouncing straight back, but at the moment I think it will be resolved in weeks rather than days."
As for Glenn Roeder's convalescence, Trevor adds: "The signs are very positive so at the moment there is every confidence to think that he should be well enough to come in and at least be involved from the off.
"Meanwhile, I have got my daughter's wedding to think about - but it will be an interesting time with more happening later in the summer."