Pompey are poised to make Gary Mackay-Steven their second signing of the summer.
The left-footed winger is out of contract at Aberdeen, where he made 30 appearances and scored seven times last season.
The free agent is expected to sign for the Blues this week, joining James Bolton as the new faces at Fratton Park so far this summer.
A Scotland international, the 28-year-old also numbers Celtic, Dundee United and Airdrie as former clubs.
At Parkhead he made 62 appearances and scored 10 times during a two-season spell.
Mackay-Steven will add competition to the wide attacking areas, with Ronan Curtis and Jamal Lowe the Blues’ regular occupants last term.
Lowe’s future remains clouded, with Pompey having already turned down bids from Millwall and Wigan during the close season.
Yet Mackay-Steven is likely to chiefly challenge Curtis for a spot on the left of the attacking three in Jackett’s favoured 4-2-3-1 system.
Being left-footed, he offers a natural option on that flank, with Curtis right-footed, albeit still enjoying an impressive maiden Pompey season last term.
The anticipated arrival of the Scot will finally end all interest in Viv Solomon-Otabor, with Pompey initially keen on turning his loan arrangement with Birmingham permanent.
Despite offering a contract to the 23-year-old, Jackett has now turned to Mackay-Steven to vie with Curtis next term.
Mackay-Steven totalled 68 apperances and 15 goals during two years at Aberdeen, joining from Celtic for an undisclosed fee in July 2017.
He last featured for Scotland in October last year, as a substitute in a 3-1 friendly defeat to Portugal.