Kenny Jackett is closing in on making Ronan Curtis his first signing of the summer.
The Blues are in advanced talks with Derry City over the 22-year-old striker.
It is understood a substantial fee is required to capture the highly-regarded goal-getter.
Yet Pompey are willing to meet such a valuation for Curtis, who is attracting plenty of interest from the Football League.
On Monday, Curtis scored a hat-trick in the 7-3 hammering of Shelbourne in the EA Sports Cup quarter-finals, taking his season’s tally to seven.
Manager Kenny Shiels had been keen to retain the Republic of Ireland under-21 international, previously speaking bullishly on the issue.
However, there is an appetite in the Derry hierarchy to cash in on Curtis, particularly with plenty of parties staking their interest.
Jackett has made no secret of his intent to strengthen his Blues squad as soon as the transfer window opens on May 17.
That date for clubs has been brought forward following a vote to implement a transfer window closure on August 9.
In the meantime, Pompey are continuing to pursue Curtis and remain in pole position to secure a deal.
Jackett is eager to bolster a striking pool which currently has Brett Pitman, Oli Hawkins and Conor Chaplin.
However, Chaplin has drifted out of the first-team reckoning at times during the second half of the campaign, raising questions over his future.
While Pompey’s boss has stated several times the necessity of adding more pace to his attacking unit to increase its potency.
Meanwhile, the Blues are expected to announce their retained list on Wednesday.