Pompey are hopeful of landing Brett Pitman on a free transfer.
The Blues have made the Ipswich striker their attacking focus, as Kenny Jackett looks to strengthen his front line.
Talks are progressing well, although Pompey are exercising caution over bringing in the 29-year-old with plenty of sides keen on securing his services.
Pitman has been told he can leave Portman Road as Mick McCarthy shakes up his options this summer.
The former Bournemouth man has a year left on his contract, but Ipswich would be prepared to let him leave without a fee.
Pitman was adamant he wanted to remain in the Championship if he was to move on from the club he joined in 2015.
But Pompey’s interest has made him reconsider that position, as Jackett looks to add some real weight to his attacking options.
He was Ipswich’s top scorer in his first season (2015-16) with 11 strikes, after bagging 14 goals in the previous campaign for the Championship-winning Cherries.
Pitman got just four goals last term in a lone striking role, however, as he side laboured to a 16th-placed finish in the second tier.
Pompey had been looking to land Dagenham & Redbridge striker Ollie Hawkins from the National League.
The Daggers haven’t been prepared to budge on their valuation, however, with a host of teams keen on the 25-year-old.
Now the prospect of Pitman moving to Fratton Park has seen them switch their attention to the 6ft striker.