Grayson said: "We're progressing nicely. We might have new faces in for the weekend or we might not. I have players in mind that I believe will improve the squad, my targets have never changed.
"I think things will happen, but we do have a group who have been top and have proved how good they are.
"We need maybe a couple of fresh faces to add competition for places and keep everyone on their toes."
Grayson added that he was in talks with Liverpool about extending goalkeeper David Martin's loan spell, which expires after Saturday's home game against Colchester.