The former Reading boss is keen to lift the Elland Road giants back to the promised land of the Premier League but admits he will have to let players go if he is to bring any in.
McDermott said: "At this stage you're trying to get players in - obviously we've got Matt Smith in and another deal agreed - then we'll just see what happens in the next couple of weeks.
"The situation is that there is a possibility that we may have to do deals going the other way with players going out to bring players in. As it stands there may have to be outgoings to get players into the club."
One player who has attracted interest from other clubs is 19-year-old defender Sam Byram - reportedly a target of cash-rich Manchester City.
But McDermott said: "I've got no interest in selling Sam Byram - but we've had a little bit of interest for one or two players so we'll just have to wheel and deal. That's how it is at this moment in time
"The situation isn't what I expected but I'm at this football club and fully committed to it. I've got a lot of time for the staff and supporters and they deserve success.
"If the club get some investment over the next month then there's a possibility that we can do deals - and I know that everyone is working very hard behind the scenes to make that happen."