As reported by the Newcastle Herald, the Knights have shown interest in Pompey as they prepare set to make some decisions regarding the future of the club.
The interest in Pompey comes after try-scoring winger Dominic Young will be departing at the end of the season, agreeing to join the Roosters, and the futures of Hymel Hunt and Enari Tuala are unknown.
Aged 24, Pompey has plenty of potential and has appeared in all 14 games for the Warriors this season. During these games, he has scored two tries, had six try assists and ran on average 107 metres per game.
While Pompey is not their number-one priority at the moment, his arrival will add an extra level of attacking presence and could fill Dominic Young's vacant wing position.
However, if Frizell does re-sign and rookie Dylan Lucas decides to take up an option for one more year, the Knights will only have four Top 30 roster spots left to fill.
Signing Pompey would leave them with three vacancies and eight off-contract players.
This means Lachlan Fitzgibbon (attracted interest from Leeds Rhinos), Kurt Mann, Adam Clune, Jack Johns, Brodie Jones, Bailey Hodgson, Hymel Hunt and Enari Tuala will be contending for the remaining vacant spots.