The Blues have identified the middle of the park needs strengthening after the poor start to the League One campaign.
Kenny Jackett's not satisfied how Tom Naylor and Bryn Morris have looked as a pair so far and instead looking for a fresh face.
Work’s presently going on behind the scenes to find that player as Pompey look to finally light the touchpaper to their campaign.
The Blues were linked with ex-Aston Villa man Jake Doyle-Hayes earlier this week.
But we’ve taken a look at some of the other engine-room operators who could potentially fit the bill...
9. George McEachran - Chelsea
The 20-year-old certainly has a good pedigree, having been capped at youth level for England throughout the age groups. McEachran had a loan spell at Dutch side Cambuur last term. Photo: Nathan Stirk
10. Mace Goodridge - Burnley
Yet to make his debut for Burnley but been on the bench in the Premier League on 13 occasions. Should Burnley get new faces in, they may allow the 21-year-old to head out on loan. Another who wouldn't count towards the salary cap. Photo: Bryn Lennon
11. Archie Collins - Exeter City
Made 45 appearances during Exeter's run to the League Two play-off final last season at the age of 21. Likely plenty more to come but is contracted until 2022 and a fee would be required. Photo: Pete Norton
12. Jensen Weir - Brighton
The highly-rated youngster joined Brighton from Wigan for a reported fee of £500,000 earlier this year. Paul Cook highly rated the England youth international during his time as Latics boss, revealing Weir was in his top three players he'd worked with for 'taking in information'. Another who'd be exempt from the salary cap. Photo: Alex Livesey