Milan Lalkovic is set to leave Pompey.
The Slovakian winger has agreed an exit from Fratton Park after a season hindered by injury.
The Blues have reached a compromise with the 25-year-old over the remainder of his contract, which ran until the summer.
Lalkovic has been dogged by an Achilles issue, which has restricted him to just two appearances this term.
In total, the former Chelsea man made 18 Blues appearances, scoring one goal.