Rovers were beaten 3-1 by Bolton in a pre-season friendly on Tuesday and Moore was upset with the way his team defended.
"You can see where we're short. The defensive part is not good at the moment," he told the club's official website.
"We could probably get an 18 or 19-year-old kid who will come in and make the same mistakes we're making now. We don't want to bring in a young lad who is going to learn the game if we can help it. But we'll keep knocking and hopefully that will change."
Moore also revealed he is still waiting for Jonathan Tehoue to make a decision on the club's contract offer.
He added: "Tehoue is umming and ahhing over what he's going to do. At the moment we've offered him a contract, he's looking for more money and we haven't got the money to give him."