Although it is only three months since the sides met at the end of last season, there has been considerable change at the Berkshire club during the summer.
Former Manchester United centre-half Jaap Stam was appointed manager in June to succeed the sacked Brian McDermott.
Stam has been active in the transfer market, making seven signings – six of them joining from clubs abroad.
North End have had scouts at most of the Royals’ friendly games, the latest being a 1-1 draw with Bournemouth at the Madejski Stadium last week.
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Reading’s goal came from John Swift, signed in the summer from Chelsea.
The young striker spent most of last season on loan at Brentford, netting in the Bees’ 3-1 win at Deepdale in January.
Grayson told the Evening Post: “We had Reading watched on Friday night and have also done so over the last few weeks.
“You try and pick the bones out of the pre-season fixtures, it is about having a guideline of how they play.
“Ultimately, it is about what we try to do in the game but you need to know about the opposition.
“Reading have changed manager and quite a few players since we last played them.
“It is a different animal to contend with but if we can get the same result as we did in April, we will be very pleased.”
North End beat the Royals 2-1 at the Madejski on April 30, that being their final away game of last term.
Jermaine Beckford opened the scoring in the 56th minute, running clear to lift a shot over the Royals keeper.
The home side levelled four minutes from time through Stephen Quinn before Daniel Johnson netted PNE’s winner in stoppage time.
Who will start for Preston on Saturday, Grayson insists he is still mulling over.
A clear week of training at Springfields will help him nail down his chosen XI and list of substitutes.
“There are still decisions to be made in terms of personnel,” said Grayson.
“The system will dictate certain personnel.
“I have got an idea of who will play but that can change over the course of the week.
“We have got a clear week in the build-up which gives us time to have a look through a few things.”
Grayson has been pleased with how North End have shaped up in pre-season.
Results-wise, PNE beat Bamber Bridge, Chorley, Oldham and Morecambe, drew with Stoke and Bolton, while they lost to Fulham in Ireland.
“The players conducted themselves in a very professional manner during the summer,” said Grayson.
“Everything we asked them to do, they gave 100% and worked very hard.
“We have done a few different things, the challenge is to get the necessary work into the players but keeping them engaged at the same time.
“The aim was to get the players as fit as possible and have as many of them available for the first day of the season.
“We had the unfortunate injury to Calum Woods but everyone else has pretty much come through it.
“The lads are now at the stage where they just want to play, they want the games to start coming thick and fast.
“It is a busy start to the season with plenty of Saturday-Tuesday football.”