Pompey will face AFC Wimbledon and Sutton in the group stages of the 2021/22 Papa John's Trophy.
Danny Cowley's side will face one of the sides at home and the other away in Group B of the Southern Section
They will also be at home to an invited Category One under-21 side, with the draw taking place at 4.30pm on Thursday (June 24) and broadcast live on Sky Sports News.
The invited clubs in the Southern Section of the draw include Arsenal, Aston Villa, Brighton, Chelsea, Crystal Palace, Southampton, Tottenham and West Ham.
AFC Wimbledon avoided relegation from League One last term, while Pompey have never previously faced Sutton in a competitive fixture.
The Londoners are gearing up for their first campaign as an EFL club after securing the National League title last term.
Papa John's Trophy Southern Section invited clubs
| Number | Team |
| 1 | Arsenal U21 |
| 2 | Aston Villa U21 |
| 3 | Brighton & Hove Albion U21 |
| 4 | Chelsea U21 |
| 5 | Crystal Palace U21 |
| 6 | Southampton U21 |
| 7 | Tottenham Hotspur U21 |
| 8 | West Ham United U21 |
Meanwhile, the Carabao Cup first round draw will also be shown live on Sky Sports News at 3.40pm on Thursday.
Pompey – who reached the second round of last season's competition – are ball number 27 in the southern section.
Carbao Cup round one draw numbers
| Number | Northern Section | Southern Section |
| 1 | Accrington Stanley | AFC Bournemouth |
| 2 | Barnsley | AFC Wimbledon |
| 3 | Barrow | Birmingham City |
| 4 | Blackburn Rovers | Bristol City |
| 5 | Blackpool | Bristol Rovers |
| 6 | Bolton Wanderers | Burton Albion |
| 7 | Bradford City | Cambridge United |
| 8 | Carlisle United | Cardiff City |
| 9 | Crewe Alexandra | Charlton Athletic |
| 10 | Derby County | Cheltenham Town |
| 11 | Doncaster Rovers | Colchester United |
| 12 | Fleetwood Town | Coventry City |
| 13 | Harrogate Town | Crawley Town |
| 14 | Hartlepool United | Exeter City |
| 15 | Huddersfield Town | Forest Green Rovers |
| 16 | Hull City | Gillingham |
| 17 | Lincoln City | Ipswich Town |
| 18 | Mansfield Town | Leyton Orient |
| 19 | Middlesbrough | Luton Town |
| 20 | Morecame | Millwall |
| 21 | Nottingham Forest | Milton Keynes Dons |
| 22 | Oldham Athletic | Newport County |
| 23 | Port Vale | Northampton Town |
| 24 | Preston North End | Oxford United |
| 25 | Rochdale | Peterborough United |
| 26 | Rotherham United | Plymouth Argyle |
| 27 | Salford City | POMPEY |
| 28 | Scunthorpe United | Queens Park Rangers |
| 29 | Sheffield United | Reading |
| 30 | Sheffield Wednesday | Stevenage |
| 31 | Shrewsbury Town | Sutton United |
| 32 | Stoke City | Swansea City |
| 33 | Sunderland | Swindon Town |
| 34 | Tranmere Rovers | Wycombe Wanderers |
| 35 | Walsall | |
| 36 | Wigan Athletic |