Assistant-boss Joe Gallen confirmed the Blues are hoping to strengthen in defence before they turn their attention to forward options.
A centre-back is on Pompey’s priority list – and preferably one who is left-footed.
We’ve taken a look at some of the options that could fit the bill for Kenny Jackett…
1. Lewis Gibson - Everton
The England youth international featured for the Toffees in their 3-3 draw with Blackpool on Saturday. If he can't force his way into Carlo Ancelotti's plans, another loan switch may be on the cards after impressing at Fleetwood last term. Gibson's left-footed, which is a key attribute that Pompey are looking for. He also wouldn't count towards the salary cap being aged 19. Photo: Daniel Chesterton
2. Cameron John - Wolves
John had a highly-fruitful spell at League One rivals Doncaster last season where he scored three times in 21 games. A move to Pompey could be seen as a step up and Kenny Jackett could use his Wolves connections to land the defender. He turned 21 today (August 24) which means he would be exempt from the salary cap. Another left-footer. Photo: Bruce Rollinson
3. Josh Knight - Leicester City
One on this list who isn't a lef-footer - but we know Pompey are interested in. Knight's hoping to concentrate on playing centre-back next season, after spending the past one-and-a-half seasons featuring in midfield at Peterborough. Knight wants a Championship club but the Blues would be keen on a deal if their are no second-tier suitors. Photo: Nigel Roddis
4. Scott Wharton - Blackburn
The 22-year-old helped Northampton to League Two play-off glory last season, scoring four goals in 43 games. Wharton is hoping to make a breakthrough at Rovers in pre-season, but another loan spell could be in the offing if he remains on the fringes. Another one who's left-footed. Photo: Pete Norton