Pompey are set to turn their keeper hunt away from David Forde.
And the Blues are also closing in on a deal for right-back Nathan Thompson.
Forde now appears unlikely to be making a return to Fratton Park next season, as Kenny Jackett looks elsewhere for his options between the sticks.
Initial discussions had taken place between the 37-year-old and the Blues, following his release from Championship side Millwall.
But they haven’t progressed further since Jackett arrived as Paul Cook’s successor.
Jackett has worked with Forde after taking him to The Den from Cardiff City in 2008.
But the man who kept 19 league clean sheets and was named in the League Two team of the year now looks to be headed elsewhere.
Pompey are progressing on strengthening their resources in the right-back position with a move for Thompson, however.
The 26-year-old, who can also play in the middle of defence is out of contract at the end of the month and will leave Swindon Town after their relegation to League Two.
The Robins’ captain was offered a new deal at the County Ground but has opted to move on after spending his senior career with the Wiltshire outfit.
A move for Thompson began while Cook was still manager at Fratton Park.
His energetic style of play fits in with the approach Jackett wants to employ.
It also points to a return to playing further up the pitch for Gareth Evans, who operated in the right-back position for most of last season.
Drew Talbot is Pompey’s other existing right-back option. He has a year remaining on his deal.