The exact severity of their injuries, both to the knee, are not yet known. However both players will miss tomorrow's pre-season friendly at Dean Court against Division Two side AFC Bournemouth.
Physio Jon Fearn revealed that the club will know more about the injuries in due course.
"We will be reviewing them (Newman's and Brown's knee injuries) over the next 24 to 48 hours but they will not be playing at Bournemouth on Tuesday," he said.
Pardew will be waiting anxiously for further news of the injuries, as Brown was a defensive mainstay for the Royals last season. Indeed, it was his form alongside Adie Williams at the back that helped to catapult the team into a top six position.
Ricky Newman, who last season made a long-awaited comeback from a knee injury that had him sidelined for eighteen months, recently signed a new one-year deal with the club. The 32-year-old had been hoping to claim a regular first team berth this season.
The Royals are suffering a mini injury crisis at the back at the minute so will likely have to draft in John Mackie to partner Adie Williams at the back tomorrow night.
Mackie himself is only just returning from injury having sustained severe brusing in training last week. Should the Londoner fail a fitness test then Pardew will have to look to teenage academy centre-backs Ahmet Rifat and Peter Castle to solve his defensive headache.
Meanwhile, striker Nicky Forster has resumed full training following his ankle ligament injury that kept him off the football fields throughout the summer.
The livewire forward, who bagged seventeen goals last season, should now be fully fit for the start of the new campaign after successfully negotiating last week's friendly games in Sweden.
"Nicky is now training fully but we will still be monitoring his ankle over the next few weeks. He has made tremendous progress and completed 60 minutes in the second tour game," added the Royals physio, speaking to readingfc.co.uk.