Grayson was on the receiving end 2-0 defeat to North End in the first round of this season's Capital One Cup while in charge of Huddersfield.
Graham Westley's heavily reshaped squad rarely scaled such heights thereafter and following the ex-Stevenage boss' departure last week, Grayson inherits a squad lying 17th in League One.
"I know quite a bit about them because they beat us in the Capital One Cup when I was at Huddersfield in the first game of the season," he said.
"There's some good players and when you look at the squad in general they're probably under-achieved. That's why a manager loses his job and a new one comes in.
"I'm aware of a lot of the players, I'll try to get the best out of them over the next few weeks, try to get some results and finish positively at the end of the season."
Meanwhile, Preston's home league game with Oldham will be played on Tuesday, April 9 at 7:45pm.
The match was due to take place on Tuesday, February 26 when Latics now face Everton in an FA Cup fifth-round replay.