While the hosts are languishing in the relegation zone, Pompey are currently leading the way at the top of the League One table.
Match preview
Reading fans are set to hold a protest against owner Dai Yongge ahead of Saturday's contest, with their off-field troubles continuing to affect matters on the pitch.
The Royals, who have been deducted four points this season, are currently dwindling in 23rd position with eight points separating them from safety.
Since beating Bolton Wanderers in mid-September, the Royals have drawn one and lost five of their previous six league matches.
In their most recent outing, Reading looked set to play out a draw with Fleetwood Town when Dominic Ballard cancelled out Bosun Lawal's opener, but a 92nd-minute winner from Josh Vela ultimately condemned Reading to a fourth consecutive loss.
Having conceded 11 goals across those four defeats, Ruben Selles will need to see a defensive improvement if his side are to trouble their in-form opponents.
In contrast to their hosts, Portsmouth are full of confidence after winning nine and drawing five of their 14 league games this season.
Pompey, who are looking to return to the second tier for the first time since 2012, currently enjoy a four-point lead over second-placed Oxford United and a four-point cushion over the sides sitting outside the automatic promotion spots.
John Mousinho's side had to be content with a point in Tuesday's goalless draw with Cambridge United, bringing an end to an eight-game winning run in all competitons.
While they may have been frustrated to miss out on a victory, the result extended Pompey's unbeaten league run to 25 matches.
Having let in just eight goals this season, Pompey currently holds the best defensive record in the third tier, and they will be looking to claim a fourth consecutive league clean sheet in Saturday's encounter.
Reading League One form:
L
D
L
L
L
L
Reading form (all competitions):
D
L
L
W
L
L
Portsmouth League One form:
W
W
W
W
W
D
Portsmouth form (all competitions):
W
W
W
W
W
D
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Team News
Reading remain without the injured quartet of Amadou Mbengue, Coniah Boyce-Clarke, Tom McIntyre and Ovie Ejaria.
Selles made the tactical decision to introduce Femi Azeez in the 30th minute of Fleetwood's contest, and after playing an hour in midweek, the midfielder is likely to feature in Saturday's starting lineup.
Sam Smith is set to make a third consecutive start since recovering from injury, and the 25-year-old is expected to be joined in the frontline by Ballard.
As for the visitors, they are still expected to be without the services of Anthony Scully, Tom Lowery and Marlon Pack.
Jack Sparkes could come into the starting lineup, with Conor Ogilvie likely to miss out after being forced off in the eighth minute against Cambridge United.
Faustino Anjorin played the final half-hour of Tuesday's contest, and the Chelsea loanee is in contention to feature in the starting XI this weekend.
Reading possible starting lineup:
Button; Bindon, Dean, Abbey, Guiness-Walker; Azeez, Savage, Wing, Knibbs; Smith, Ballard
Portsmouth possible starting lineup:
Norris; Swanson, Poole, Shaughnessy, Sparkes; Morrell, Robertson; Lane, Anjorin, Kamara; Bishop