Tom Naylor and Ross McCrorie handed Pompey an injury boost by returning to training on Monday.
Both had been absent for recent games because of hamstring setbacks.
But while manager Kenny Jackett indicated an instant recall to the Blues’ match-day squad, Saturday’s home game against Peterborough in League One looks a more likely return date.
Central defender Sean Raggett is expected to start – alongside Paul Downing – in defence following his return from an abductor injury.
Meanwhile, Andy Cannon is likely to earn his first starting XI place since the trip to Oxford in the group stages of the EFL Trophy.
Youngsters Alex Bass, Harvey Rew and Leon Maloney are also expected to feature as Jackett continues his approach of giving youth a chance in the competition.
Northampton have already used 20 players in this season’s EFL Trophy to date.
And manager Keith Curle looks set to utilise his squad again for the visit to Fratton Park.
Regular first-teamers Jordan Turnbull, Scott Wharton, Sam Hoskins, Chris Lines and Andy Williams are likely to feature as the Cobblers look to stretch their unbeaten run in all competitions to nine games.
But Curle may opt to call on several fringe players as high-flying Northampton keep one eye on Saturday’s League Two game against fellow promotion-chasers Exeter.