The former Reading boss, who was only appointed in April following the departure of Neil Warnock, admitted this week that any further new signings may have to be funded by player sales.
And with the Elland Road faithful hoping for an influx of talent to drive them back towards the Premier League for the first time in 10 years, expectations have had to be tempered.
McDermott told the Yorkshire Evening Post: "That's a frustration that we have all got. I can empathise with that frustration (from the fans); I have had that myself.
"But there's no point being frustrated, that doesn't help. In my situation, I have to keep my head down and keep working as hard as I possibly can and stay positive.
"That's what we have got to do as the alternative to positive is negative."
McDermott insists he is not allowing himself to become downhearted by the obstacles which have emerged in his path and is focused on returning the West Yorkshire club to a place among England's elite.
He added: "It's the absolute opposite. I like the challenge and the people around here. I have got no problem 'digging in'.
"I have just a real commitment to this place and area now. The people have been really welcoming and I will do whatever I have to; I guarantee that.
"I haven't been here very long, but I have a real sense from the people here that they want this club to grow, get better and be better.
"We have the potential to be a really, really good club and need to respect and cherish that. There's a lot of goodwill towards me and I really appreciate that. I go to functions with the fans and everything and see that.
"I cannot talk about the past - just about what is happening now. We really need to be as positive as we possibly can be and go forward together."