Pompey will discover their Papa John's Trophy third round opponents when the draw takes place at 11.15am on Thursday.
It will be broadcast live on TalkSPORT 2, presented by former Blues commentator Dan Windle and conducted by ex-Preston and Stoke striker Jon Parkin.
The draw is still regionalised at this stage, so Kenny Jackett's side could face AFC Wimbledon, Bristol Rovers, Cambridge, MK Dons, Northampton, Oxford or Peterborough.
Pompey are the competiton holders following their memorable penalty shoot-out victory over Sunderland at Wembley in 2019 and are still waiting to learn of a date for last season's postponed final against Salford.