Pompey could start life in the bottom tier of English football with as many as 11 new faces to choose from for this season's opener.
In an attempt to steady the ship, boss Guy Whittingham has brought in a host of players including Monaco's Romain Padovani and Hull duo Danny East and Sonny Bradley.
Despite that, Whittingham will have to make do without influential centre-back Ricardo Rocha, who failed to agree terms on a new deal at the south coast club.
Oxford boss Chris Wilder could hand veteran striker Dave Kitson his first start against his former club.
The 33-year-old, who joined from Sheffield United earlier in the summer, is in contention to make his U's debut should Wilder wish to freshen things up in attack.
He has plenty of defensive options, with new signings Jonathan Meades, David Hunt, Tom Newey and Johnny Mullins vying for a place in the matchday squad.
Midfielders Danny Rose and Asa Hall could also make their debuts.